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State Responsibility for Transboundary Air Pollution in International Law$

Phoebe Okowa

Print publication date: 2000

Print ISBN-13: 9780198260974

Published to Oxford Scholarship Online: March 2012

DOI: 10.1093/acprof:oso/9780198260974.001.0001

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General International Law and Transboundary Air Pollution: Norms, Concepts, and Principles

General International Law and Transboundary Air Pollution: Norms, Concepts, and Principles

Chapter:
(p.60) 3 General International Law and Transboundary Air Pollution: Norms, Concepts, and Principles
Source:
State Responsibility for Transboundary Air Pollution in International Law
Author(s):

Phoebe N. Okowa

Publisher:
Oxford University Press
DOI:10.1093/acprof:oso/9780198260974.003.0004

Abstract and Keywords

This chapter considers the customary international law principles that are relevant to transboundary air pollution. It suggests that, despite the rudimentary character of the customary law regime, it retains undoubted significance in view of the limited scope of the treaty instruments. Not all states presently affected by transboundary air pollution are party to the treaty regimes, and in the case of civil uses of nuclear energy there are no generally accepted treaty standards. As a result, the responsibility of states for radioactive contamination largely depends on the normative content of customary law. A case for the progressive development of the law is also made and a critique of the emergent norms and principles is undertaken.

Keywords:   transboundary air pollution, international law, treaty regimes, radioactive contamination, customary law

3.1. Introduction

Notwithstanding the proliferation of a large number of legal instruments regulating transboundary air pollution, discussed in the previous chapter, the restraints imposed by customary law and other general principles retain considerable significance. There are a number of reasons for this. First, the treaty regimes discussed in the last chapter are in most cases considerably general in character and do not contain sharply defined standards of conduct. In many cases there is also a general absence of precision in relation to the terms used. Their practical operation is thus dependent on existing or at least emergent standards of conduct under general international law. Furthermore, the norms and standards contained in the treaty instruments are concerned with the prevention of pollution, and in general they do not regulate issues of responsibility for damage that might arise in the event of non-compliance with treaty provisions. Thus, issues of responsibility fall to be determined under the regime of general international law.

In any case, the inherent assumptions as to the efficacy of treaty regulatory regimes are not always borne out in practice. For a start, a significant number of states may choose to opt out of treaty regimes. In the case of transboundary air pollution it was noted that a significant number of states contributing to pollution have at various stages chosen not to participate in the regimes created by the treaty instruments.1 For those states a large measure of their rights and duties vis à vis other states still depends on the content of customary rules.

Furthermore, there is considerable support for the view that the performance and the interpretation of treaties are subject to emergent standards of conduct in the international community.2 This rule, which finds expression in (p.61) Article 31(3)(c) of the 1969 Vienna Convention on the Law of Treaties,3 is particularly significant in the field of transboundary air pollution where applicable standards and ‘best practice’ are constantly changing to take account of developments in scientific knowledge. In the Gabčikovo/Nagymaros case, Hungary had argued that the 1977 treaty entered into between it and Slovakia for purposes of building a dam on the Danube had to be interpreted and applied in light of subsequent legal developments in the environmental field.4 These developments, Hungary noted, had the status of customary law and should override the 1977 treaty as lex specialis in the event of conflict.

The International Court accepted the substance of the Hungarian argument, but noted that the specific terms of the treaty had envisaged its interpretation and revision in light of new developments. Referring to the 1977 treaty the Court noted that it was ‘not static, and is open to adapt to emerging norms of international law’.5 The Court thus rejected Slovakia's argument that the provisions of a bilateral treaty as lex specialis could not be overridden or modified by new standards of general international law.6 This formal finding by the Court is bound to have a positive impact on the large number of environmental treaties, including those in the field of air pollution, which may have been negotiated against the background of outdated standards. Their continued relevance will in many cases depend on developments in general international law.

In any case, in so far as treaty regimes contain rigid amendment procedures, usually requiring the consent of all the parties, the development of general principles of customary law which can be adapted to changing situations retains undoubted significance.

Third, there is increasing support for the view that a large number of obligations in the environmental field, such as serious or massive air pollution, have an erga omnes character.7 It is suggested that the concept of erga (p.62) omnes obligations only makes sense in relation to norms that have passed into the corpus of general international law. Although this category of obligations is controversial, their recognition as such nevertheless plays a crucial role in reinforcing the importance that the international community attaches to environmental obligations. In Chapter 7, the argument is developed that the erga omnes character of some air pollution obligations may entitle all states to resort to general international law remedies including self-help in the event of breach.8

Finally, it may be argued that the retention of customary norms regulating air pollution has a certain moral appeal. It reinforces the fundamental importance of environmental obligations, and that demands for environmental protection do not disappear in the absence of treaty commitments or even if such commitments are abrogated.

(i) The Problem of Sources

It should be stated at the outset that customary law does not contain a normative regime specific to the environment as such. What one finds is a reservoir of concepts and principles of a general character on the nature and limits of sovereign rights, and which can be applied to problems of transboundary air pollution.9 The generality of these concepts and their evolution in the context of limited environmental awareness means that in most cases their contribution to contemporary environmental problems is of a modest character.10 Nevertheless, they retain a particular significance and, in the absence of more specific norms, remain the applicable law in relation to most harms of a transboundary character, including radioactive contamination. The (p.63) applicability of these concepts to transboundary air pollution as well as their inherent limits will be considered in the first part of this chapter.

In the literature, as well as in the pronouncements of international organizations, it has been suggested that the unique nature of the problems associated with environmental degradation calls for the development of new norms of a customary law character specifically tailored for the protection of the environment.11 These problems relate in particular to the cumulative nature of the processes of environmental degradation, the irreversible nature of these processes, and the multiplicity of parties contributing to the problem.12 It has also been suggested that the inherently bilateral character of the customary law approach ignores the increasing scientific evidence that the biosphere is indivisible, and that environmental degradation in one state necessarily affects the interests of all states in the atmosphere as an ecological unity.13

Suggestions have therefore been made for the use of a conceptual approach similar to that employed in the context of human rights law.14 Like human rights, it has been suggested that the non-observance of environmental standards by a state should be the concern of all states irrespective of the location of interests affected. A second approach also drawing on human rights law calls for the recognition of the right to a clean environment as a distinct human right.15 Any form of pollution that threatens this right would therefore be the basis for the imposition of state responsibility at the instance of any states or individual. This chapter thus considers the extent to which it can be said that there is a case for developing new norms of a customary law character, and the extent to which such norms can be said to be emerging in state practice.

In assessing the emergent norms of customary law it is perhaps worth pointing out that in this context the boundaries between lex lata and de lege ferenda are not always easy to delineate. State practice is haphazard and difficult to identify and in most cases it cannot be said that it has occurred in a manner that indicates unequivocally that a rule of law has evolved. Apart from the proliferation of treaties in which broadly similar duties are formulated, it is difficult to identify a coherent body of practice outside the treaty (p.64) regimes, either in the context of environmental protection generally or more specifically in the context of transboundary air pollution.16 There are few instances of inter-state disputes relating to transboundary air pollution that have been dealt with explicitly on the basis of legal rules.17

In any case caution is required in evaluating state practice under treaty regimes, for states parties to such instruments are under a treaty obligation to act in accordance with their terms.18 Moreover, the provisions of many of those treaties are only explicable on the assumption that customary law is silent on the issues they regulate. It would thus be necessary to show that even in the absence of the treaty the states in question regarded their conduct as mandatory under customary law.

In this context, it may be recalled that in determining the existence of custom, the applicable standards are those laid down by the International Court in the North Sea Continental Shelf Cases. The Court had observed that

Although the passage of only a short period of time is not necessarily, or of itself a bar to the formation of a new rule of customary law on the basis of what was originally a purely conventional rule, an indispensable requirement would be that within the period in question, short though it might be, state practice, including that of states whose interests are specially affected, should have been extensive and virtually uniform in the sense of the provision invoked;— and should moreover have occurred in such a way as to show a general recognition that a rule of law or legal obligation is involved.19

In examining the content of customary norms, the relevant practice will not be confined to the field of air pollution, but will extend to state practice in the field of marine and fresh water pollution, pollution of the seas, and other activities leading to transboundary damage. Developments in these areas are relevant since the basic problems raised by them are similar to the new problems in the area of air pollution, even if they may differ in matters of detail.

(p.65) 3.2. The Basic Principles Reconsidered

(i) The Concept of Territorial Sovereignty

The sovereignty that a state enjoys in respect of its territory embodies a catalogue of rights and duties the character of which as lex lata is not in doubt.20 Thus, it is generally accepted that territorial sovereignty confers a licence on a state to exploit and enjoy the resources within its territorial confines. But the freedom is double-edged, in so far as it also requires source states to respect equally the sovereignty of others and refrain from conduct that may be injurious to other states in a manner that is contrary to the rules of international law.21 In particular, it is generally accepted that where a state harbours a source of harm on its territory, it is in principle responsible to other states that may suffer injury as a result.22 The obligations of the source state to prevent harm to others is grounded on the actual or presumed control that international law vests in it.23 It follows from this principle that the state is responsible for polluting activities directly operated by it as well as those under private control.24

A number of judicial decisions, multilateral and bilateral treaties, diplomatic exchanges, as well as resolutions of international organizations, discussed below, may be cited in support of the basic proposition that a state ‘is not permitted to use its territory for purposes injurious to the interests of other states’. This principle has been reaffirmed repeatedly and its legal quality is not in doubt.25 However, much uncertainty has centred on its practical application, and in particular the standard of conduct required of states in (p.66) specific situations. Nevertheless, it is increasingly accepted that it involves a duty to exercise control over sources of transboundary harm and to pay reparation for any resultant damage.

There is a substantial body of opinion in both the literature and in state practice supporting the application of these principles to environmental damage and more specifically to transboundary air pollution. The proposition that ‘a state must not permit the use of its territory for purposes injurious to the interests of other states in a manner contrary to international law’ commands considerable support in the literature and in the practice of states.26 Brownlie, for instance, has observed that respect for territorial sovereignty provides a basis for the imposition of state responsibility on a sovereign state ‘causing, maintaining, or failing to control a source of nuisance to other states’.27 It is necessary to examine the evidence in some detail in order to delineate the exact parameters of state obligations under customary law.

(ii) Jurisprudence

The obligation of states to ensure that activities under their jurisdiction and control do not cause harm to the territory of other states finds support in the jurisprudence of arbitral tribunals that have considered the issue. Although some of the arbitral decisions considered below were not directly concerned with transboundary pollution, the relevant legal principles were formulated at a high level of generality and would therefore be equally applicable to transboundary air pollution. In the San Juan River Case 28 an arbitral Tribunal was established by Costa Rica and Nicaragua to delimit their common boundary in accordance with the terms of the Canas-Jeres Treaty.29 Although concerned with the interpretation of the terms of a water treaty, a number of pronouncements were made by Grover Cleveland, President of the United States, acting as arbitrator, which are relevant to the present inquiry. He observed that

(p.67) The Republic of Costa Rica cannot prevent the Republic of Nicaragua from executing … within her own territory … works of improvement, provided such works of improvement do not result in the occupation or flooding or damage of Costa Rica territory, or in the destruction or serious impairment of the navigation of the said river or any of its branches at any point where Costa Rica is entitled to navigate the same. The Republic of Costa Rica has the right to demand indemnification for any lands on the same bank [of the River San Juan] which may be … flooded or damaged in any other way in consequence of works of improvement. The natural rights of the Republic of Costa Rica … are to be deemed injured in any case where the territory belonging to the Republic of Costa Rica is occupied or flooded.30

The precedent value of the above passage has to be approached with caution since the arbitrator was strictly speaking interpreting the terms of an applicable treaty, and was not directly concerned with the determination of general principles that would apply across the board. Nevertheless the passage cited was couched in the most general terms and must be taken to be a reflection of the applicable principles of general international law, especially given the status of the arbitrator. As McCaffrey has suggested, the award supports the general proposition that the rules of international law prohibit states from causing flooding damage to the territory of others, and that the breach of this obligation entails the duty to make reparation.31 It is further suggested that there are no reasons of principle why the pronouncements in this arbitral award should not be equally applied to transboundary air pollution.

The decision of the international arbitral tribunal in the Trail Smelter Case provides a lucid exposition of the nature of the obligation of states to prevent transboundary harm in the specific context of transboundary air pollution. It also remains one of the few environmental disputes to reach an international tribunal.

This was a dispute concerning transboundary air pollution between the United States and Canada. A Canadian company at Trail in British Columbia was emitting sulphur dioxide fumes, which, as the tribunal found, were causing damage to crops and timber in the State of Washington. In reaching its decision the tribunal was considerably influenced by a compro-missory agreement between the two parties, in which the responsibility of Canada as the defendant state was assumed. It was therefore primarily concerned with the apportionment of damage and not with the formulation of general rules.

However, in an often-cited passage the tribunal concluded

that under the principles of international law, as well as the law of the United States, no state has the right to use or permit the use of its territory in such a manner as to (p.68) cause injury by fumes in or to the territory of another or the properties of persons therein, when the case is of serious consequence and the injury is established by clear and convincing evidence.32

The tribunal was unable to find international precedents of direct relevance, and in formulating the above passage relied principally on the decisions of United States Courts on inter-state litigation concerning transboundary harm. It is, however, significant that the tribunal was of the view that the decisions of the United States Courts were in keeping with the principles of international law in the same context. Although the passage referred to was strictly speaking obiter, there is little doubt that it was grounded on basic principles of international law.33

In the Corfu Channel case, the International Court was faced with the issue of Albanian responsibility for the presence of mines in its territorial waters, which posed danger to international navigation. The Court referred to certain general and well-recognized principles in support of the proposition that every state was under a duty not ‘to allow knowingly its territory to be used for acts contrary to the rights of others’.34 Although concerned with the application of the law in a different context, the pronouncements made by the Court have nevertheless been regarded as of general application.35

In any case the general principle under consideration has also received the explicit endorsement of the International Court in its recent jurisprudence. In its advisory opinion on the Legality of the Threat or Use of Nuclear Weapons, the Court noted that ‘existence of the general obligation of states to ensure that activities within their jurisdiction and control respect the environment of other states or of areas beyond national control is now part of the corpus of international law relating to the environment’.36 The large number of states that submitted written statements to the Court in connection with the advisory opinions on legality of nuclear weapons clearly accepted this obligation.37

The decision by the International Arbitral Tribunal in the Lake Lanoux case has also been cited in support of the proposition under consideration.38 The tribunal was called upon to decide a dispute between France and Spain concerning the diversion of the waters of Lake Lanoux by France. It found that the proposed works by France would not result in diminution of the water volume flowing into Spanish territory. However, it envisaged a hypothetical (p.69) situation where the proposed works would damage Spanish interests through chemical or thermal pollution, and concluded that in that situation the responsibility of France would be engaged.39

These decisions provide cogent evidence of what international tribunals regard as the applicable principles in cases of transboundary injury. It is suggested that the generality of the basic principles articulated in the arbitral decisions is relevant to transboundary air pollution, and their value is not diminished by the unique factual and legal context of the disputes on which they were based.

(iii) State Practice

Several statements made by state representatives in various contexts, including actual disputes, also indicate that the conduct of activities on state territory is subject to legal regulation, and that in particular, states are responsible for any harm caused to the territory of other states. The principle that no state may use its territory in such a manner as to cause injury to the territory of other states received the express endorsement of the United Nations Conference on the Human Environment. Principle 21 provides that

States have in accordance with the Charter of the United Nations and the principles of international law, the sovereign right to exploit their own resources pursuant to their own environmental policies, and the responsibility to ensure that activities within their jurisdiction or control do not cause damage to the environment of other states or areas beyond the limits of national jurisdiction.40

The Principle has been relied on by Canada in relation to air pollution disputes with the United States.41 In the 1995 Nuclear Tests Cases, both France and New Zealand accepted the normative rule contained in the Principle 21 as one of general application, but differed on the precise legal consequences that attach to its application42 Similarly, both parties to the Gabčikovo-Nagymaros dispute accepted without qualification that the rule contained in (p.70) Principle 21 was the starting point in any assessment of state obligations in the environmental field.43

The positions taken by Canada and the United States in relation to the Gut Dam dispute also provide some evidence of what the two states regarded as the applicable rules of international law in cases of transboundary harm44 In this case Canada compensated United States' citizens for damage caused to their property as a result of a rise in the level of the lake partly attributable to a dam constructed by Canada. The dam had been built by Canada across the St Lawrence River with the consent of the United States, on the express understanding that Canada would compensate United States citizens for any losses attributable to the dam.

In the ensuing correspondence relating to the compensation of the United States' citizens, Canada confirmed to the United States' Secretary of State, Dean Acheson, that in principle it was under a duty to pay compensation for damage caused. The value of this communication is diminished by the fact that Canada was already under a treaty obligation to pay compensation, a commitment which was in fact the basis of United States consent to the construction of the dam. However, as McCaffrey has pointed out, even in the absence of the agreement Canada would have been bound to pay compensation to the United States under general international law.45 There is no evidence to suggest that Canada ever denied that it had an obligation to pay compensation even in the absence of a treaty commitment.

The Australian and New Zealand claims in the Nuclear Tests Cases were partly based on the assertion that the carrying out of an activity that causes harm to the territory of other states is illegal and a violation of state sovereignty in its territorial and decisional aspects.46 The legitimacy of this claim is considered in some detail in the next chapter in relation to responsibility for radioactive contamination. However, the generality of the arguments put forward by Australia and New Zealand makes a consideration of their positions equally relevant here.

In its Memorial, the Australian Government put forward the proposition that the violation of a state's sovereignty per se was a justiciable issue even in the absence of damage. Australia's primary argument was that

(p.71) the intrusion alone of a harmful substance violates her rights for which violation satisfaction may be awarded and that further, and additionally, the harmful substance which has intruded because of acts for which France is responsible inflicts serious, even though it may be presently incalculable, harm or damage to Australia and its population. Those rules of international law which have been long applied yield the result, so we will submit, that France is responsible.47

However, Australia did not regard every intrusion no matter how insignificant as the proper object of redress. It maintained a distinction between industrial pollution and atmospheric nuclear tests. The former, it argued, was subject to a ‘deminimis’ rule and could under existing rules of international law only be a proper object of claim if a certain threshold of harm had been sustained.48 In reply to a question by Judge Sir Humphrey Waldock, Australia observed that

Where as a result of a normal and natural use by one state of its territory, a deposit occurs in the territory of another, the latter has no cause of complaint unless it suffers more than nominal harm or damage. The use by a state of its territory for the conduct of atmospheric nuclear tests is not a normal or natural use of its territory. The Australian Government also contends that radioactive deposit from French tests gives rise to more than merely nominal harm or damage to Australia.

the basic principle is that intrusion of any sort into foreign territory is an infringement of sovereignty. Needless to say, the Government of Australia does not deny that the practice of states has modified the application of this principle in respect of the interdependence of territories. It has already referred to the instance of smoke drifting across national boundaries. It concedes that there may be no illegality in respect of types of chemical fumes in the absence of special types of harm. What it does emphasise is that the legality thus sanctioned by the practice of states is the outcome of the toleration extended to certain activities which are generally regarded as a natural use of territory in modern industrial society and are tolerated because, while perhaps producing some inconvenience, they may have a community benefit.

The merits of the argument that the general rules on tolerable levels of harm are much more stringent in the case of nuclear contamination is considered in some depth in the next chapter. Although the Court did not make a substantive finding on the claim by Australia following its conclusion that the dispute was moot as a result of the French undertaking not to continue the tests, it is significant that a number of judges in their dissenting opinions were of the view that the Australian claim was well founded in law.49 Moreover, it (p.72) deserves to be emphasized that since in the international system states tend not to bring claims unless they believe them to be well founded in law,50 the applications provide cogent evidence that, in the opinion of Australia and New Zealand, customary international law enjoined states not to cause significant transboundary air pollution.

France did not appear in the 1974 Nuclear Tests Cases, but it is significant that in its statements relating to the claims made against her, she did not contest Australia's basic proposition that physical contamination of a state's territory entailed the responsibility of the contaminating state. This position was reiterated in the French Aide-Mémoire submitted in connection with the 1995 Nuclear Tests Cases brought by New Zealand as well as in the oral proceedings in the same case.51 The point of difference between France and these States related to France's insistence that in the absence of proven damage the mere contamination of a state's territory could not engage her responsibility. In a White Paper issued in 1973 in connection with nuclear tests, France observed that

Regarding environmental protection, positive law remains primarily based on the obligation to compensate for proven damages when there is a violation of an accepted norm. Nowhere does the law prohibit tests because of purely hypothetical risks. If suggestions have been made along different lines, this very fact suffices to show that positive law is indeed what it has just been said to be.52

In the 1995 case France accepted that there was an obligation not to cause environmental harm, but that no question of responsibility could arise in the absence of proven damage. Referring to the New Zealand argument that France was responsible for damage to the marine environment, the French Counsel, M. Perrin de Brichambaut, made the following observations:

New Zealand which is incapable of adducing evidence of damage or even serious risk … affirms that the new environmental law has the effect of reversing the burden of (p.73) proof. Even though we have willingly demonstrated the precautions taken by France, which as the Court has seen are supported by widely circulated scientific data, it still remains that international law recognises no ecological exception in the matter of evidence. Environmental law, like other fields of law, obeys the well known principle of actori incumbit probatio and therefore New Zealand must base its allegations on something other than the worst-case scenarios encouraged by the undeniable talent of its counsel. Specifically in connection with damage that can be equated with transboundary damage, so often found where the environment is concerned, the International Court of Justice in its judgment in the Corfu Channel Case rejected the plea of self-evidence and we do not believe that international law on this point has changed.53

Therefore, it may be concluded with a degree of certainty that Australia, France, and New Zealand in varying contexts accepted that existing principles of international law prohibited the causing of damage to the territory of other states. The principal difference related to the question of whether quantifiable damage was of the essence of the right to territorial integrity.

A more recent case of responsibility for pollution damage which was grounded on the principle of the inviolability of territorial sovereignty is the claim made by Canada for damage caused by the Soviet Cosmos 954. The claim was partly grounded on the 1972 Convention on International Liability for Damage Caused by Space Objects,54 but Canada also based the claim on the applicable principles of general international law. It noted in part that

The intrusion of the Cosmos 954 satellite into Canada's air space and the deposit on Canadian territory of hazardous radioactive debris from the satellite constitutes a violation of Canada's sovereignty. This violation is established by the mere fact of the trespass of the satellite, the harmful consequences of this intrusion being the damage caused to Canada by the presence of hazardous radioactive debris and the interference with the sovereign right of Canada to determine the acts that will be performed on its territory. International precedents recognize that a violation of sovereignty gives rise to an obligation to pay compensation.55

The claim was settled ex gratia and the Soviet Union never admitted liability, a fact which on its face must necessarily exclude the extrapolation of principles of a general nature. In any case a degree of caution is called for in assessing the precedent value of this settlement, since ex-gratia payments are usually made without prejudice to the legal position of either party. Second, although the Canadian claim was partly grounded on existing rules of general international law, the 1972 Convention on International Liability for Damage caused by Space Objects, on which it was based, provided for the inescapable liability of the Soviet Union for damage of the kind suffered by (p.74) Canada. It is therefore not clear whether the customary law basis of the claim was acceptable to the Soviet Union.

Nevertheless, it is significant that in the opinion of the Canadian Government the liability of the Soviet Union existed under customary law even in the absence of the treaty commitment. There is in any case no evidence to suggest that the Soviet Union ever denied that it had such an obligation.

The relations between a number of European states are also predicated on the supposed impermissibility of activities that cause significant transboundary harm. Franco-German relations have largely been conducted on this premiss. In one instance France had proposed to build a chemical industrial complex at Ottmarsheim, but abandoned the construction of certain factories after it emerged that their operation would cause serious air pollution to the German villages in Baden-Wurttemberg.56 Of those retained France specifically adopted advanced technical means to prevent transfrontier pollution.

The discussions between the two states did not directly involve a consideration of the applicable legal principles. Nevertheless, the fact that the project was abandoned as a direct result of the German protestations provides some indication that the two states did not regard the causing of transboundary pollution as acceptable under international law.

France also responded to German complaints that a proposed lead sulphate factory in Marckolsheim entailed the risk of serious transboundary harm. On this occasion the German complaints were firmly grounded on legal principles, including a Resolution of the Committee of Ministers of the Council of Europe Concerning Air Pollution in Frontier Areas and OECD principles concerning transfrontier pollution. France was willing to take into account German air quality standards, but the project was shelved owing to opposition from the local population in Alsace.57

The relations between the Netherlands and Belgium are also illustrative. During 1971–2 the Belgian Government decided to build an oil refinery on the river Meuse, where the river forms a boundary between Belgium and the Netherlands. The Dutch Government, fearing that this would lead to water and air pollution in the border area, protested to the Belgian Government. After a series of consultations between the two countries, an agreement was reached which took into account the Dutch protestations.58 The debates in the Belgian House of Representatives indicate that the consultations were regarded as a normal procedure of good neighbourly relations.59 This, of course, leaves open the question whether such consultations were regarded as legally mandatory. While it cannot be stated categorically that the consultations (p.75) were held out of a sense of legal obligation, it nevertheless provides cogent evidence that in the opinion of the Belgian Government, activities on state territory had to anticipate adverse effects on the territory of other states.

Although concerned with potential environmental damage in the context of the use of international watercourses, the arguments of the parties in the Gabčikovo-Nagymaros dispute are equally relevant here. Both parties accepted that international law required states to adopt measures that would prevent environmental damage. The point of difference between them was essentially whether the 1977 bilateral treaty between them provided an appropriate framework for taking environmental concerns into account.60

(iv) The Position Taken in International Instruments

It has already been noted that the obligation of states to ensure that activities under their jurisdiction or control do not cause transboundary harm received the imprimatur of the 1972 United Nations Conference on the Human Environment and the 1992 Rio de Janeiro Conference on the Environment and Development.61 Both Conferences were convened to discuss actions necessary at the international and national levels in order to limit, and where possible eliminate, the impairment of the human environment.

It has been noted that Principle 21 of the final declaration adopted by the Stockholm Conference and Principle 3 of the Rio Declaration reaffirmed unanimously the basic principle of harm prevention, and responsibility for any damage sustained by other states. Principle 21 received the overwhelming support of the member-states of the United Nations,62 and has been confirmed in almost all the treaty instruments relating to the protection of the human environment,63 as well as in the works of the non-official bodies of international lawyers.64

(p.76) (v) Some Conclusions

It is submitted that apart from the absence of claims following on the Chernobyl nuclear accident, there is no evidence in the modern practice to contradict the proposition that states are under an obligation to ensure that activities on their territory do not cause transboundary harm.65 The difficulties presented for this thesis by the Chernobyl accident are examined in some detail in the next chapter, as Chernobyl presents a number of problems peculiar to itself. The failure of states to make any claims following the accident and the Soviet Union's persistent denial of any basis for legal responsibility must be placed in the context of the unique political and economic circumstances of the accident. As is argued in the next chapter, the absence of claims following Chernobyl is best seen as an instance of waiver of what are otherwise bona fide claims.

In light of the evidence discussed above, and despite some flaws in the practice of states, it is submitted that contemporary international law prohibits states from carrying out activities in a manner that causes injury to the territory of other states. This conclusion, it should be noted, is at variance with that of Professor Schachter, who notes that the principle prohibiting significant pollution is still de lege ferenda and must await the appropriate developments in the practice of states and opinio juris to endow it with the authority of customary law.66 He notes that notwithstanding the existence of the duty to prevent transboundary harm, states do not generally ensure that activities under their jurisdiction and control do not cause such transboundary harm.

With respect, this argument confuses the existence of a right and its observance in actual practice. While it is true that there are still numerous cases of transboundary harm, these should in principle be treated as breaches of the rule rather than the affirmation of a contrary principle.67 There is no evidence in contemporary international law of a state asserting that international law does not impose any restraints on the conduct of activities that cause harm to others.

Although it is clear that the rule of prohibition as formulated requires the prevention of harm and reparation for resultant damage, it also raises difficult issues of practical application if the ultimate goal is to be realized. For (p.77) instance, what standard of conduct is required of states under the rule? Are there any principles or standards that a state is required to observe in pursuit of the goal of prevention? The level of damage triggering responsibility also requires further definition.

It is argued in the following section that, although there is an emerging consensus that states are required to exercise due diligence in order to prevent transboundary air pollution, there is little agreement as to what this involves in practice. As a result the application of the basic rule is, to say the least, problematic and partly accounts for the dearth of state claims in contemporary international relations.

3.3. Standard of Performance

(i) Introduction

In general, the question whether a state has complied with the requisite standard of conduct or not will only arise when its responsibility is called into question. The context need not be an inter-state claim, for issues of non-compliance may very well arise when a state's conduct is called into question before a supervisory organ charged with implementing a treaty regime. It is nevertheless helpful to consider what the basic principles of state responsibility are, for they provide an appropriate framework for analysing the standard of conduct expected of states in the field of transboundary air pollution. The rest of this section will attempt to define the normative content of the general obligation to prevent transboundary harm that has been considered in the previous sections.

The majority of writers as well as the decisions of international tribunals support the objective theory of responsibility. According to this theory, the breach of an obligation engages the responsibility of a state even in the absence of culpable conduct or want of care on its part. Certain defences may be available, such as act of third party, force majeure, and voluntary assumption of risk, but, on the whole, provided that a relationship of cause and effect is established, there is breach of duty by result alone.68

The theory operates at the general level and it is accepted that it may be modified or qualified by the content of a specific obligation. Thus, it may be the case that a rule only calls into question the responsibility of a state in the (p.78) presence of some culpable conduct or want of care on its part. In other words, the legal context will determine the degree of advertence expected of a state before its responsibility can be called into question. Thus, as a general rule responsibility is not predicated upon culpa or dolus unless the instrument creating the obligation requires such further qualification.69 The objective element of responsibility is satisfied by the mere occurrence of conduct at variance with that expected of the state. In this sense objective responsibility is the international equivalent of the municipal concept of strict liability.

However, a small number of eminent writers have regarded fault as the proper basis of responsibility.70 The erroneous premisses on which their conclusions were based have been consistently pointed out in the literature.71 The authorities they cite were instances where the substantive obligation in question was formulated to make fault a condition of responsibility. It is therefore erroneous to conclude that in all instances fault is a condition of responsibility. Moreover, as Bin Cheng has noted, confusion arises because of the fact that in many instances writers and tribunals employ the terminology of fault to denote the fact that a particular state is in breach of its international obligation.72

Having noted that the standard of performance depends on the exact formulation of the obligation in question, it may be asked what, then, are the applicable standards of conduct required by substantive rules in the field of transboundary air pollution? Duties may impose varying degrees of strictness, ranging from a relatively strict standard in the case of inherently risky activities such as nuclear operations, to a due diligence standard in the case of industrial and automobile emissions. The standard applicable to nuclear pollution is considered in some detail in the next chapter.

Simply stated, what is a state required to do in order to ensure that activities carried out under its jurisdiction and control do not cause transboundary air pollution? Does international law lay down any standards or principles to be observed, and are states held responsible for any harm occurring notwithstanding the observance of such standards?

(p.79) (ii) Due Diligence

There is general acceptance in international instruments that what is reasonable conduct will depend on the means at the disposal of the particular state. A considerable number of writers,73 as well as the non-official bodies of international lawyers, have argued on the basis of state and treaty practice that the duty to prevent transboundary harm requires states to do no more than exercise diligent control over the sources of harm under their jurisdiction and control. Thus, Jimenez de Aréchaga has observed that ‘failure to exercise due diligence is not synonymous with malice, negligence or recklessness’. It simply means that a state has failed to meet the standard of conduct expected of a reasonable government in the circumstances. The Restatement also adopts a due diligence standard. Section 601 provides that

(1) A state is obligated to take such measures as may be necessary to the extent practicable under the circumstances, to ensure that activities within its jurisdiction or control are conducted* so as not to cause significant injury to the environment of another state or of areas beyond the limits of national jurisdiction.

The Restatement specifies the nature of conduct expected: it must conform to generally accepted international rules and standards. It is clear that subsection (a) was influenced by a similar formulation in the 1982 Law of the Sea Convention.74

Several other treaties in the field of the environment, including those that apply to transboundary air pollution, relate the state's duties to its socioeconomic capabilities. It was noted in Chapter 2 that Article 2 of the 1979 ECE treaty requires states parties to ‘endeavour to limit, and as far as possible gradually reduce and prevent, air pollution’. Similar terminology is employed in the 1980 EEC Council Resolution on Transboundary Air Pollution by Sulphur Dioxide and Suspended Particulates. The resolution obliges member-states to endeavour ‘to limit and as far as possible gradually reduce and prevent transfrontier air pollution’.75 Although the specific obligations assumed by the parties to the 1991 Air Quality Agreement are not qualified to take into account the capacity of the states parties, Article XIV expressly notes that the fulfilment of those duties by the parties shall be subject to the availability of funds in (p.80) accordance with constitutional provisions.76 In general the language employed in the 1979 ECE Convention and its Protocols, the Air Quality Agreement between the United States and Canada, and the relevant EEC directives, indicates that states are required to reduce pollution progressively, having regard in particular to the means at their disposal.77

The ILA has also formulated state obligations in this context in terms of a requirement of ‘due diligence’. Draft article 3 adopted by the Committee on the Legal Aspects of Transboundary Air Pollution provides that

(1) states shall take all appropriate measures to prevent and, as far as possible, gradually abate long-distance transfrontier air pollution originating in their [territory] [the area under their jurisdiction].78 [emphasis supplied]

The Article goes on to qualify the basic obligation of the states to take into account ‘their economic capacity and the need to maintain balanced development’ as well as the cost and effectiveness of the measures.

Similarly, Article 2 of the Draft Articles adopted by the Institute of International Law in the context of air pollution requires states to take ‘all appropriate and effective measures to ensure that the activities conducted within their jurisdiction or under their control cause no transboundary air pollution’. An earlier draft that had stated the obligation of the parties in absolute terms attracted much criticism from the members of the Institute and was amended in the terms stated above.79

The United Nations Conference on Environment and Development also implicitly endorsed the due diligence obligation, by providing that measures to prevent environmental degradation need not be absolute but must be integrated into the development process, in each case taking into account the resources at the disposal of the particular state.80

In the Case Concerning the Gabčikovo-Nagymaros Project, Hungary argued that

(p.81) the duty of prevention is not … an absolute one. Whether the state has fulfilled its obligations in this regard is measured by the rule of due diligence … In the context of the present case, due diligence is the means by which the general principle of the harmless use of territory is to be applied taking into account the specific elements of the situation.81

The Hungarian proposition was not contested by the Slovak Republic as a matter of principle, although the latter maintained that in the circumstances it had done all that could be expected of a reasonable government mindful of its international obligations.82 One can, therefore, conclude that general international law does not as such require states to be guarantors against pollution. Instead, they are only expected to take all necessary measures as may be expected of a reasonable government in the circumstances.

3.4. Compliance With Due Diligence: What Measures?

The conclusion that due diligence is the applicable standard nevertheless begs the question as to what specific measures are to be adopted by a state in complying with this duty. It has been noted that in the literature and in the jurisprudence of international tribunals there is support for the view that the effectiveness or reasonableness of the measures will all depend on the capacity or means at the disposal of the particular state.83 Thus in the Salvador Prats Case, the Mexico-United States Mixed Claims Commission held that: ‘The duty of protection on the part of the government, either by the general principles of international law or by especial agreement of the treaties, only goes as far as permitted by possibility’.84 But how is this capacity to be assessed? Does international law adopt an objective or a subjective test in determining whether the state has done all that is expected of it under a due diligence standard? Is the plea of the state that it could not possibly comply with its obligations as stipulated conclusive?

As a matter of principle, it is arguable that a subjective approach to due diligence is irreconcilable with the idea of a legal regime against the background of which state conduct is to be tested. Why have standards, if ultimately the (p.82) state is the final arbiter of whether or not its conduct in any situation was compatible with international norms?

International tribunals that have considered the question of due diligence have generally reached the conclusion that the correctness of a state's application of the law to the facts is subject to international supervision. In each case the conduct of the state must be subjected to an international standard.85 In the Neer Case the Mexico-United States General Claims Commission stated that the conduct of the Mexican state in failing to apprehend and punish those guilty of murdering an American citizen should be subjected to an international standard. Finding that the Mexican state had not failed in its due diligence obligations, the Commission stated the applicable law in the following terms:

that the propriety of governmental acts should be put to the test of international standards and that the treatment of an alien, in order to constitute an international delinquency, should amount to an outrage, to bad faith, to wilful neglect of duty, or to an insufficiency of governmental action so far short of international standards that every reasonable and impartial man would readily recognize its insufficiency.86

In the Case Concerning the Gabčikovo-Nagymaros Project, Hungary noted that in determining whether a state had in fact discharged the due diligence obligations imposed on it, account had to be taken of the nature of the activity.87 The standard it maintained was not a subjective one but rather had to be tested against the background of what could be expected of a reasonable government faced with the same situation. Slovakia did not contest the argument that the standard expected of states was not absolute, but noted that on the facts it had done all that could be expected of a diligent government mindful of its environmental obligations.88 In making these arguments in the context of litigation, Hungary was implicitly asserting that the reasonableness of measures adopted was subject to international supervision.

In the 1995 Nuclear Tests Cases, New Zealand argued that France could only show that it had complied with the due diligence obligations imposed on it by demonstrating that it had conducted an environmental impact assessment which was externally verifiable and which conclusively demonstrated that no environmental harm would occur. As is noted later in this chapter, the correctness of this approach to due diligence may be open to doubt. However, it is significant for present purposes that New Zealand took the view that whether or not a state had complied with its due diligence obligation was a (p.83) matter open to external verification by reference to international law standards.89 The application of an international standard to due diligence obligations also finds support in most of the existing literature.90

It would be presumptuous to attempt to prescribe a specific set of conduct that a state must conform to by way of discharging its due diligence obligations. Despite the considerable range of contexts in which the term is used, there is little evidence that it is desirable to define its content in the abstract. Like many areas of law that call for the application of law to the facts, what amounts to diligent conduct will be a matter of appreciation. This is especially the case since appropriateness of the conduct will not just depend on regional or international standards but also the economic capacity of the particular state.91 A set of factors to be taken into account may evolve in state practice, and there is increasing evidence that minimum standards of what is expected of a diligent government are beginning to emerge.

(i) Due Diligence and the Emerging Principles in the Field of Environmental Protection

Several attempts have been made in state practice as well as in the work of codification bodies to define the conduct expected of a state by way of discharging its due diligence obligations.

The appearance of a large number of principles that are deemed of fundamental importance are bound to have a considerable influence on the interpretation of the content of due diligence obligation of states. Of central importance is the concept of sustainable development. The concept, as formulated in Principle 4 of the Rio Declaration, provides that

In order to achieve sustainable development, environmental protection shall constitute an integral part of the development process and cannot be considered in isolation from it.92

In one sense, sustainable development is no more than an obvious application of the idea that measures to protect the environment cannot be divorced from issues of state capacity and its other development concerns. To this extent sustainable development is no more than a formal restatement of ideas inherent (p.84) in the concept of due diligence, which as noted in the previous pages has always hinged on the means at the disposal of the particular state.

Nevertheless the formal reaffirmation reinforces the idea that measures to protect the environment are not absolute, and cannot be considered in isolation from the economic means and developmental concerns of the particular state.93 In relation to transboundary air pollution, it may actually mean that a certain amount of transboundary pollution may have to be tolerated by a victim state if the benefits from the activity are considerable, and the state in question has done its best to abate the pollution.94 In Chapter 2 it was noted that some European states that had only achieved a modest state of development, such as Greece, Spain, and Ireland, opposed the adoption of uniform obligations as unfair. Their insistence that measures to protect transboundary air pollution must take into account the means and developmental concerns of states is reflected in the provisions of the 1979 ECE treaty and its Protocols.95

Two other emergent principles are also frequently referred to as having influenced the content of due diligence obligation of states. Thus the principle of precaution and the duty to carry out environmental impact assessment are increasingly referred to in state practice as indispensable elements of the due diligence obligation of states.96 The best formulation of the principle of precaution is to be found in Principle 15 of the Rio Declaration which provides that

In order to protect the environment, the precautionary approach shall be widely applied by states according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost effective measures to prevent environmental degradation.97

The legal status of this principle has been the subject of varying interpretations in the literature.98 It is suggested that the principle has no free-standing legal value, but none the less may be an important element in determining the (p.85) content of the due diligence obligations of states.99 The exercise of precaution may require a state to conduct environmental impact assessments before embarking on an activity that may entail serious transboundary harm. In each case this will depend on the context.100 It is suggested that there is little evidence to support the proposition that such assessments are mandatory in all instances.

In any case, it is significant that the principle of precaution has affected the position of the parties in two recent cases to come before the International Court. The parties to the 1995 Nuclear Tests Cases accepted the principle of precaution as directive in fulfilling their obligations to prevent transboundary harm. However, they fundamentally differed as to what this entailed. In the opinion of New Zealand, the principle of precaution dictated that no activity should be allowed to take place unless adequate environmental impact assessments had been carried out, the findings of which indicated that no environmental harm would result. New Zealand argued that it was inconceivable that a state would be able to discharge its duty to prevent environmental harm without there being a legal duty to ensure, in advance, that an activity does not involve any unacceptable risk to the environment.101

More specifically, counsel for New Zealand argued that France could not seriously assert that it was preventing, reducing, and controlling pollution resulting from its nuclear activities as required by international law obligations imposed on it, in the absence of such an environmental impact assessment. In the course of oral argument Mr Mackay made the following observations:

Once the environment is protected by law, the requirement of an environmental impact assessment follows by logical and practical necessity. Once it is accepted that there is an obligation to protect the environment, as a matter of legal duty, it is a logical corollary to demand that, in recognition of this duty, anyone contemplating an activity which may harm the environment must—I repeat, must—as a matter of legal duty first establish that the activity does not involve any unacceptable risk to the environment.

Thus there is no need to look for a specific, legal obligation to conduct EIA. That duty flows from the legal duty to protect the environment: it is logically inseparable. You cannot have a legal duty to protect the environment without there being a legal duty to ensure, in advance, that an activity in contemplation does not contain a risk to the environment. The two necessarily go hand-in-hand.

(p.86) The fact that the means whereby a party ensures that there is risk to the environment is nowadays called EIA is purely coincidental. The EIA is simply a convenient term to describe a process whereby a party carries out a clear, legal duty.102 [emphasis supplied]

It was also New Zealand's contention that the principle of precaution as formulated in Principle 15 of the Rio Declaration and other applicable treaties had the effect of reversing the burden of proof, and that the burden was on France to prove that the proposed nuclear tests did not entail any damage for the environment.103

This was rejected by counsel for France, who maintained that the principle of precaution did not have the inflexible content attributed to it by New Zealand. In his view, it required no more than the adoption of reasonable preventive measures. He rejected New Zealand's contention that the effect of the precautionary principle was to reverse the burden of proof, by shifting the onus on those proposing or conducting particular activities to demonstrate that no environmental harm would occur. Although he accepted in principle that an activity had to anticipate its effects on the environment, he maintained that the mechanisms for anticipating potential harm were flexible and did not have to follow any fixed procedure. In explicitly rejecting New Zealand's contention that a state could only carry out an activity if environmental impact assessment had clearly shown that no harm would result, he observed that

Despite its name, ‘impact assessment’, this type of measure leaves each State … with a considerable margin of discretion as to how it ensures, before undertaking potentially dangerous activities, that the effect of such activities on the environment will not be detrimental. Each state has to adapt its methods of appraisal to the type of activity, the environment and the technologies involved.104

In the Gabčikovo-Nagymaros Case, again both Hungary and Slovakia accepted that in discharging their obligations of prevention they should be guided by the precautionary principle but disagreed on its practical implications. Hungary argued at length that the obligation of states to ensure that activities on their territory did not cause significant transboundary harm implied a subsidiary duty to conduct environmental impact assessment.105 Secondly, like New Zealand in the 1995 Case, Hungary also argued that the (p.87) burden was on Slovakia to demonstrate that no harm would result from the proposed activities.

Slovakia did not contest that the conduct of such an assessment was an important part of the process of discharging the due diligence obligation imposed on states, but argued that on the facts appropriate assessments had in fact been carried out as required by the terms of the applicable treaty. It further maintained that the standard involved in preventing transboundary harm was not inflexible or absolute, but had to be assessed in light of all other factors, including the right of states to exploit their natural resources in accordance with their developmental needs. In the course of oral argument counsel for Slovakia argued that

to interpret the precautionary principle to prevent development projects unless all uncertainty—that is 100% of the uncertainty—were eliminated would be to stop development. It would require a state to establish with complete certainty that absolutely no environmental problems of the kind referred to would arise. It would require proof of a negative proposition—something any lawyer would recognise to be nearly impossible. What principle 15 does say is that where there are threats of serious or irreversible damage, the lack of full scientific certainty that such damage will occur should not cause postponement of cost effective measures of prevention.106

(ii) Some Conclusions

It is suggested that the argument that the precautionary principle requires states to refrain from the conduct of activities in all instances where they cannot prove that no environmental harm will result, cannot be a correct application of the ‘due diligence obligation of states’. Such a rigid interpretation finds no support in the negotiating history of the concept at the Rio conference 107 and is moreover juridically impossible to reconcile with the view accepted in arbitral tribunals that due diligence depends on the means and the capacity of the particular state. It is also irreconcilable with the concept of sustainable development, which requires a balancing act between a state's developmental needs and its environmental concerns.

Although the two principles of precaution and sustainable development are important in directing state behaviour, it is suggested that they are nevertheless of limited legal value, since what is an adequate precautionary response as well the implications of sustainable development are context-specific. They do not contain normative principles of general application.

The evidence from state practice nevertheless supports the view that the conduct of an appropriate environmental impact assessment, or an equivalent mechanism, will in most cases be an important means of discharging the (p.88) due diligence obligations imposed on states. However, as is argued in Chapter 5, there is no evidence to suggest that general international law requires these assessments to take a particular form or to apply in all cases.108

(iii) Thresholds of Tolerance

It may also be noted for the sake of completeness that the duty to prevent transboundary harm also embodies a de minimis test. A state is not required to prevent all harm; only that which is appreciable, significant, or substantial.109 The de minimis test is in part a necessary corollary of the argument made in the previous paragraphs that states are only expected to exercise due diligence in controlling sources of harm.

The de minimis rule may be qualified in cases where the transboundary harm is caused by radioactive contamination. There is support for the view that there are no levels below which radiation can be deemed safe, and that the mere occurrence of radioactive contamination crosses the threshold of tolerable pollution. The precise nature of the threshold of harm in relation to atmospheric nuclear tests was the subject of disagreement between Australia and France in the Nuclear Tests Cases. Australia was of the view that the mere involuntary receipt of radioactive fall-out was an appropriate basis for the imposition of responsibility, given the inherently harmful character of radioactive contaminants.110 France in response maintained that the right to territorial integrity amounted to no more than a right not to be subjected to actual and demonstrable damage by radioactive contaminants.111 It is suggested in the next chapter that the rules relating to thresholds of tolerance may be different in relation to radioactive contamination. It was noted in Chapter 1 that there is considerable support for the view that there is no level below which radiation can be said to be harmless, and that as a result any exposure, no matter how small, should not be tolerated unless accompanied by compensating benefits.

In relation to contamination from industrial and other stationary sources, it is generally accepted that in a world where states must physically coexist a measure of environmental contamination must be tolerated. In the absence of specific air quality standards the determination of tolerable harm is problematic. In the practice of states, judicial decisions, and the literature, it is clear (p.89) that not all harm is prohibited. The harm suffered, it is frequently said, must be serious, appreciable, considerable, significant, or in some cases substantial. It is only when these thresholds are reached that the harm suffered becomes legally relevant under international law.112

The Trail Smelter Case provides the earliest evidence of impermissible levels of harm under international law. In that case the tribunal concluded that injury triggering international responsibility must be of ‘serious consequence’ and it must be established by clear and convincing evidence. This is indeed a very high threshold by today's standards, although at the time of the decision there was very little environmental awareness. Lower thresholds of tolerance may be justified by reference to the precautionary principle. It was noted that although this principle at the present time lacks a clear normative content it should be treated as a particular application of the due diligence obligation of states, in so far as it calls for caution in the face of scientific uncertainty.113

The words ‘significant’ or ‘substantial’ are frequently used in treaties on environmental protection to denote impermissible levels of harm.114 The main non-official bodies concerned with the development of international law as well as the ILC also favour the setting of thresholds at significant harm.115

Although there is increasingly a move away from ‘seriousness’ as the threshold of harm, the alternative terms of significant or appreciable harm raise many problems of definition and the quantitative limit implicit in the terms cannot be stated with certainty.116 In situations where states have (p.90) agreed on quality standards or maximum levels of emissions the determination of significant harm is largely conditioned by the agreed standards. Unfortunately, binding quality standards or maximum permissible levels of emissions of general application cannot be said to exist under general international law, and treaty regimes have on the whole refrained from imposing precise standards.

Ultimately what amounts to the prohibited threshold is a question of fact and the adjudicating or supervisory body has a wide margin of appreciation in determining whether or not the threshold has been attained. Regional standards of behaviour and expectations, the pattern of treaty obligations, and the availability of technology the application of which could have prevented the transmission of pollutants, as well as the state of scientific knowledge, and the means at the disposal of a particular state, will all play a part in the determination of the impermissible threshold of tolerable harm.

3.5. Norms De Lege Ferenda: A Progressive Regime

It was suggested at the start of this chapter that customary international law does not contain a regime specific to transboundary air pollution. What one finds is the application and adaptation of pre-existing principles to the new problems in the environmental field. A distinct issue is whether or not there is a case for the development of new principles, concepts, and even mandatory norms peculiar to the environment and, in the context of the present enquiry, to transboundary air pollution.

Proponents of new norms argue that traditional international law is an inadequate means of responding to environmental problems, since much of that law was formulated at a time of limited environmental awareness, and in many ways did not take ecological values into account. A persistent criticism of customary law in this context is that it only provides a remedy ex post facto, after the damaging consequences have occurred, and is impotent in face of anticipated or threatened harm.117

A second concern for proponents of change emphasizes the fundamental importance of environment interests. It is thus argued that this importance should be reflected in new norms that have a higher status than those traditionally used to reconcile conflicting claims to sovereign rights. Thus, it is argued that obligations for the protection of the environment (in this context including transboundary air pollution) are not discrete bilateral obligations, but are instead parallel obligations for the protection of the interests of the (p.91) international community and should be treated as binding erga omnes.118 Further, it is argued that the international system should permit an actio popularis, and any member of the international community should be able to bring an enforcement action before international forums.119 Although these suggestions undoubtedly have implications for the content of the normative regime, their potential value in strengthening the effectiveness of the legal regime under consideration will be examined in Chapter 7 in the context of remedies and the procedures for obtaining them.

Others adopt a more radical approach and call for the elimination of the state system, and its replacement with a supranational authority with responsibility for safeguarding the global environment in the interest of the whole of mankind. They emphasize the ecological unity of the physical environment and that the sovereign state cannot be trusted to safeguard these interests for the common good. The suggestion that the state system should be replaced with a supranational authority is controversial, and raises many large questions that are beyond the scope of the present work. It suffices to say that such radical alternatives have not found support with governments or international lawyers.120

However, several new conceptual and theoretical approaches have been suggested to meet these perceived shortcomings of traditional international law. Some of these, it is suggested, are programmatic and aspirational, and should not be taken as the articulation of immediately binding legal obligations. Others, such as the principle of precaution and the procedural duties of environmental impact assessment, consultation and exchange of information, while not established rules of customary law, nevertheless have considerable relevance as mechanisms for discharging the due diligence obligations imposed on states. It is necessary to look at each of these in turn in order to determine their potential relevance in the prevention of transboundary air pollution.

(p.92) (i) The Precautionary Principle

One of the central weaknesses of the international system is the absence of a developed system of remedies that could effectively deal with threatened or anticipated harm.121 The Case Concerning the Gabčikovo-Nagymaros Project remains one of the few cases where the parties specifically asked for injunctive relief in the face of threatened harm. In fact, it was noted in the previous paragraphs that much of the customary law obligations applicable to transboundary pollution are retrospective in character and only come into play after injury has occurred. The emergence of the ‘precautionary principle’122 has arisen from the recognition that most processes of environmental degradation are irreversible. There is thus a concern that activities carrying with them a significant risk of irreversible environmental harm should be regulated so as to prevent transboundary harm, and where necessary prohibited by law, even if scientific uncertainty remains as to the nature of the damage that is likely to result from them.

Thus, in the literature it is increasingly suggested that preventive measures should be taken even if the risk of damage is uncertain or remote, and that on the whole states should err on the side of caution even where future risks are unknown.123

The content of this principle is far from unambiguous, and the limited state practice referred to previously indicates that it is subject to a number of differing interpretations. It has been suggested that the principle requires that states should take measures to prevent pollution even if the deleterious effects of such pollution remain unproven, and that the burden is on the state indulging in the polluting activity to prove that its actions are in fact harmless.124 It has therefore been suggested that the application of the principle entails a reversal of the burden of proof as traditionally understood.125

Yet there is also a respectable body of opinion that doubts whether the principle has any independent legal value.126 It has been suggested that the (p.93) principle requires no more than a common-sense approach to the prevention of environmental damage: in particular, that realistic cost-effective measures that could prevent environmental damage should not be postponed merely because the likelihood of the damage is far from certain.127 So formulated, it adds nothing to the accepted principle that in assessing the content of the due diligence obligation of states, attention must be paid to the economic resources at the disposal of the particular state. It is suggested that at the present time there is little evidence to support the thesis that the precautionary principle embodies distinct normative consequences for states; it is no more than a non-binding guiding precept. There is no evidence that it already requires states, for instance, to abandon the construction of nuclear installations because the installations entail an unacceptable risk of transboundary harm. The point is succinctly made by Birnie and Boyle:

Despite its attractions, the great variety of interpretations given to the precautionary principle, and the novel and far reaching effects of some applications suggest that it is not yet a principle of international law. Difficult questions concerning the point at which it becomes applicable to any given activity remain unanswered and seriously undermine its normative character and practical utiliy …,128

The principle nevertheless provides the impetus for the negotiation and adoption of concrete obligations in treaty instruments directed at prevention of air pollution even in the face of scientific uncertainty. Thus, the many treaty and other non-binding instruments that provide for procedural duties of prior impact assessment, exchange of information, notification and consultation, discussed in Chapter 5, can easily be justified by reference to the precautionary principle.

(ii) The Right to a Healthy and Ecologically Balanced Environment

This approach borrows from international human rights law. On this reasoning it is argued that international law either already recognizes or should recognize the rights of individuals and groups to a clean and sound environment as an independent human right.129 This would be in addition to the many (p.94) categories of human rights already recognized by international treaties and customary law. Proponents of this approach argue that human rights are not a closed category and that the international community may create new rights to meet the changing concerns of the international society.130

While in principle there is merit in the argument that the categories of human rights are infinite, it has also been suggested that to create new rights as a matter of political rhetoric may in itself debase the entire system of protecting fundamental rights through law.131 If these new rights are to be recognized at customary law or in treaty regimes, it must arise out of a sense of conviction that such a radical step is required.

In the environmental context, it is not clear what a right formulated in such terms entails. What amount of air pollution, for instance, would be unacceptable under a right to a clean environment? To whom is the duty owed and against whom may the duty be enforced? Would this human right be classified as a collective or an individual right?132 What form does compliance take? Many writers therefore remain sceptical about the value of creating a human right to a clean environment.133 Professor Henkin has concluded in this context that: ‘At bottom, efforts to declare these to be human rights are pleas for international co-operation to address major problems facing the human race. 134

It would have been easy to dismiss the potential value of utilizing a rights language in the environmental context. However, such an approach has received the attention of the United Nations Commission on Human Rights. In 1994 the Commission received a final report on Human Rights and the Environment, prepared by its Special Rapporteur Mrs Ksentini.135 The report examines the relationship between human rights and the environment. It also proposes the adoption of a set of draft principles, many of which would (p.95) be relevant to transboundary air pollution. These Principles declare, among others,

  1. (1) a right to a secure, healthy, and ecologically sound environment;

  2. (2) a right to an environment adequate to meet equitably the needs of present generations and that does not impair the rights of future generations to meet equitably their needs.

It goes to provide a further set of individual environmental rights. These include a right of all persons:
  1. (1) to freedom from pollution, environmental degradation, and activities that adversely affect the environment, threaten life, health, livelihood, well-being, or sustainable development within, or across or outside national boundaries;

  2. (2) to the highest attainable standard of health free from environmental harm;

  3. (3) to timely assistance in the event of natural or technological or other human-caused catastrophes.

A number of procedural rights of individuals are also included. Thus Principle 15 provides that:
  1. 1. All persons have the right to information concerning the environment. This includes information, howsoever compiled, on actions or courses of conduct that may affect the environment and information to enable public participation in decision making. The information shall be timely, clear, understandable, and available without undue financial burden to the applicant.

A specific obligation is imposed on states in Principle 22. It provides that:
  1. 1. All states shall respect and ensure the right to a secure, healthy, and ecologically sound environment. Accordingly, they shall adopt administrative, legislative, and other measures to effectively implement the rights in this Declaration.

  2. 2. The measures shall aim at the prevention of environmental harm, at the provision of adequate remedies, and at the sustainable use of natural resources and shall include, inter alia:

    1. (a) collection and dissemination of information concerning the environment;

    2. (b) prior assessment and control, licensing, regulation, or prohibition of activities and substances potentially harmful to the environment;

    3. (c) measures aimed at ensuring that the international transnational corporations, wherever they operate, carry out their duties of protection, sustainable development and respect for human rights.

The cool reception that the Report has received is perfectly understandable for two reasons.136 First, the so-called duties of states contained in the draft (p.96) principles are no more than a reformulation of the obligation of states as found in existing environmental treaties and other non-binding instruments. It is doubtful that any practical value will result from their repackaging as such.137 Second, in the absence of procedural mechanisms for enforcing individual rights, the so-called human rights, say to a clean environment or to be free from pollution, are no more than obligations of state in disguise. Again, to describe them as the rights of the individual does not advance the argument much further, nor does it necessarily result in a more effective enforcement of environmental duties.

(iii) Intergenerational Equities

A third approach, most developed in the writings of Professor Brown Weiss, employs a trust concept and argues that states are mere trustees of the environment, and that a duty is owed to future generations to leave the environment in as good a state as one found it in.138 She argues that this requires sustaining the life support systems of the planet, ecological processes, and the environmental conditions necessary for a healthy and decent environment. Presumably this would require states to desist from pollution if this would involve leaving the environment in a worse state.

This last approach has attracted criticism from writers.139 It is difficult to see what practical value can be derived from it. In many ways it amounts to no more than a statement of concern which ought to influence in some way present policy choices. The point is succinctly made by Birnie when she notes that

To accord rights so to determine regulations now to unborn groups of unknown size and location, even if one accepted the theoretical premises on which this proposal is based, does not help us accurately to determine the content of current regulations. The appointment of an ombudsman for future generations, who would, on their behalf, influence the scope of current regulations, is surely an impractical suggestion.140

(iv) The Principle of Non-Discrimination

This principle requires states to ensure that activities carried out on their territories do not result in environmental harm to the territories of third states, where the resulting harm would not be tolerated in the source state itself. In other words, the principle of non-discrimination subjects transboundary pollution (p.97) to a national standard of treatment. It grants affected individuals equal access to the courts of a state whose activities are causing transboundary harm on the same terms as nationals of that state. However, its main limitation as a potential basis for customary norms lies in the fact that levels of pollution tolerance in the source state may be very high indeed, thus providing ineffective protection to the victim of pollution.

Although international instruments increasingly require states to allow foreign victims of transboundary air pollution equal access to domestic remedies available in the source state,141 there is no evidence that the principle of non-discrimination can effectively act as a substitute for the resolution of transboundary disputes at the inter-state level. It certainly has considerable value in the resolution of small transfrontier disputes affecting a limited number of litigants, as in the Trail Smelter Case. In Chapter 7 the argument is made that the principle of non-discrimination has limited or no value in the resolution of disputes of the Chernobyl magnitude, involving a large number of claimants residing in different states.

(v) Procedural Obligations

Perhaps the most important category of obligations to emerge in the environmental field are those that require states to observe a number of procedural safeguards before conducting or permitting the carrying out of any activities that entail significant damage for the environment. These duties of environmental impact assessment, exchange of information, notification, and consultation are given extended treatment in Chapter 5.142 Although the argument is made that these obligations have not passed into the corpus of general international law, it is suggested that they nevertheless play an important part in determining the content of the due diligence obligation of states. A state that has failed to conduct environmental impact assessment, enter into consultation with the putative victim, or notify the public and allow for their participation in the decision-making process, can hardly claim that it has effectively discharged its due diligence obligations should environmental harm result.

Notes:

(1) Only twenty-one states ratified the 1985 Sulphur Protocol; this excluded some of the major pollutants such as the UK and the USA, 1985 Helsinki Protocol on the Reduction of Sulphur Emissions or their Transboundary Fluxes by at least 30 per cent, 27 ILM (1988) at 698 (in force 2 September 1987).

(2) See Separate Opinion of Vice-President Weeramantry, Gabčikovo-Nagymaros dispute, 1997 ICJ reports, 88–119. In the 1995 Nuclear Tests Cases (New Zealand v. France), New Zealand strenuously argued that the legality of the French nuclear tests had to be examined against the background of applicable treaty regimes as well as generally accepted international standards, in particular the obligation to conduct environmental impact assessment: Request for an Examination of the Situation, 21 August 1995, New Zealand documents para 89; Aide-Mémoire of New Zealand, 5 September 1995 para 41, and CR, 11 and 12 September 1995, para 78. See also Legality of the Threat or Use of Nuclear Weapons (Request for an Advisory Opinion by the United Nations General Assembly), Statement of the Government of the United Kingdom, June 1995, para 3.94 at 63; A. McNair, The Law of Treaties (London, 1961) at 466; I. Sinclair, The Vienna Convention on the Law of Treaties, 2nd edn. (Manchester, 1984) at 139; N. Kontou, The Termination and Revision of Treaties in Light of New Customary International Law (Clarendon Press, Oxford, 1994); P. Reuter, Introduction to the Law of Treaties (London, 1989); Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) Notwithstanding Security Council Resolution 276 (1970) Advisory Opinion, ICJ Reports 1971 at 16 ff. and 31.

(3) Vienna Convention on the Law of Treaties, 8 ILM (1969) at 679 (in force 27 January 1980).

(4) Counter-Memorial of the Republic of Hungary, Vol. 1, 5 December 1994, para 4.22 and para 6.17; Reply of the Republic of Hungary, Vol. 1, 20 June 1995, para 3.127 and 3.128.

(5) Above n. 2, paras 111–13; for comment see P. N. Okowa, ‘Case concerning the Gabčikovo-Nagymaros Project (Hungary/Slovakia)’ 1998 ICLQ at 688.

(6) Memorial of the Slovak Republic, Vol. I, 2 May 1994, at 349–50, para 8.111 and Counter-Memorial of the Slovak Republic, Vol. 1, 5 December 1994, Chapter IX, para 9.03.

(7) Memorial of the Republic of Hungary, Vol. I, 2 May 1994, para 6.63. See also arguments of New Zealand in the 1973 Nuclear Tests Cases, ICJ Pleadings, Vol. II at 143, at 209 (para 206) and at 247, 264–6; 1995 Nuclear Tests Cases, (New Zealand v. France), Application for Permission to Intervene Under the Terms of Article 62 of the Statute Submitted by the Government of Australia, 23 August 1995, paras 18 and 33; Applications submitted by the Governments of Samoa, Solomon Islands, Marshall Islands, Federated States of Micronesia, paras 16 and 20 (text in New Zealand Ministry of Foreign Affairs and Trade, French Nuclear Testing in the Pacific (Wellington, 1996). The problems that erga omnes obligations give rise to in the environmental field are noted by Vice-President Weeramantry in his separate opinion in the Gabčikovo-Nagymaros Case above n. 2, at 88; M. Ragazzi, The Concept of International Obligations Erga Omnes (Oxford, 1997) at 154–63.

(8) K. Zemanek, ‘General Course on Public International Law’, 266 Recueil Des Cours (1997) 13 at 257.

(9) J. G. Lammers, Pollution of International Watercourses (Dordrecht, 1984) at 556–84; Brownlie, ‘A Survey of Customary Law Rules for the Protection of the Environment’, in L. A. Teclaff and A. E. Utton (eds.), International Environmental Law (New York, 1974) at 1; F. Orrégo Vicuna, ‘State Responsibility, Liability, and Remedial Measures under International Law: New Criteria for Environmental Protection’, in E. Brown Weiss (ed.), Environmental Change and International Law (Tokyo, 1992) at 125.

(10) A. Hurrell and B. Kingsbury, The International Politics of the Environment (Oxford, 1992) at 26; A. Kiss and D. Shelton, International Environmental Law (London, 1991) at 6; Brownlie,n. 9 above at 1; I. Brownlie, ‘General Course on Public International Law’, 255 Recueil Des Cours (1995) at 193; Zemanek,n. 8 above at 257; P. Birnie and A. Boyle, International Law and the Environment (Oxford, 1992) at 83.

(11) Kiss and Shelton,n. 10 above at 6–7; Brownlie,n. 10 above at 193; Birnie and Boyle,n. 10 above; L. Henkin, ‘General Course on Public International Law’, 216 Recueil Des Cours (1989) at 124.

(12) Orrégo Vicuna,n. 8 above at 132.

(13) See separate opinion of Vice-President Weeramantry in the Gabčikovo-Nagymaros Case,n. 2 above. On the erga omnes character of environmental obligations see Memorial of the Republic of Hungary,n. 3 above; 1995 Nuclear Tests Cases, application for Intervention by Australia,n. 6 above; see also applications for intervention submitted by the governments of Samoa, Solomon Islands, Marshall Islands, and the Federated States of Micronesia,n. 7 above, paras 14 and 20 at 118–19; A. Kiss, 175 Recueil des Cours (1982), at 109, 125, and 229–32; B. Smith, State Responsibility and the Marine Environment (Oxford, 1988) at 105.

(14) Nuclear Tests Cases (1978), ICJ Pleadings, Annex 10 at 375.

(15) For an excellent discussion of the issues raised in this context see A. Boyle and M. Anderson, Human Rights Approaches to Environmental Protection (Oxford, 1996).

(16) The Institute of International Law, and the International Law Association rely almost exclusively on treaty and non-binding instruments in their restatement of existing rules as well as in their suggestion de lege ferenda of what ought to be the normative principles in this context. See, for instance, ILA, Committee on Legal Aspects of Long-Distance Air Pollution, 61st Conference (Paris, 1984) at 377–412; see also Legal Aspects of Long-Distance Air Pollution, Interim Report of the Committee on the Legal Problems of Long-Distance Continuous and Instantaneous Air Pollution, 62nd Conference (Seoul, 1986) at 198–204; Institute of International Law, ‘Air Pollution Across National Frontiers’ (1987, Cairo Session) at 193–229. The problems involved in identifying the relevant rules of customary law are extensively considered in P. N. Okowa, ‘Procedural Obligations in International Environmental Agreements’, 64 BYBIL (1996) at 275–336.

(17) But see Trail Smelter Case, III RIAA at 1905.

(18) Lotus Case, Ser. A, No. 10, PCIJ (1927) at 27; L. Koepelmanas, ‘Custom as a Means of the Creation of International Law’, 18 BYBIL (1937) at 136–7; H. Lauterpacht, The Development of International Law (London, 1958) at 377–80; J. G. Lammers, Pollution of International Watercourses,n. 9 above at 154–5.

(19) ICJ Reports (1969), at 3 and 43; see also Nicaragua v. United States, ICJ Reports (1986) at 14.

(20) See the Award of Max Huber in the Island of Palmas Case, II RIAA at 839; Declaration on Principles of International Law Concerning Friendly Relations Among States, GA Res. 2625 (XXV); Article 111(3) of the Charter of the OAU; Henkin,n. 12 at 124; see also the joint dissent of judges Onyeama, Dillard, Jiménez de Aréchaga, and Sir Humphrey Waldock, Nuclear Tests Cases, ICJ Reports (1974) at 312 and 367; H. Waldock, ‘A General Course on Public International Law’, 106 Recueil des Cours (1962) at 156–7.

(21) Institute of International Law, Madrid Resolution, Vol. 24 (1911), at 365, Rule 1; OʼConnell, International Law (London, 1970) Vol. I, at 318–20; Smith, State Responsibility,n. 13 above.

(22) O. Schachter, International Law in Theory and in Practice (Dordrecht, 1991) at 63; Brownlie, in Teclaff and Utton (eds.),n. 9 above at 1–2.

(23) Corfu Channel Case, British Memorial (1949) ICJ Pleadings para 92; I. Brownlie, State Responsibility (Part I) (Oxford, 1983) at 163–5; I. Brownlie, ‘International Law and the Use of Force by Armed Bands’, 7 ICLQ (1958) at 712.

(24) Brownlie, State Responsibility,n. 23 above at 165.

(25) The principle received the express endorsement of the majority of states that submitted recent statements in connection with the Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons (General Assembly Request). See written statement by the United States at 39; Solomon Islands, at 81, paras 4.9, 4.10, 4.11, and 4.16; Islamic Republic of Iran at 4; Arab Republic of Egypt, at 17–18 esp. para 32. See also Legality of the Use by a State of Nuclear Weapons in Armed Conflict (WHO Request), Statements by the Government of Nauru at 42–4 and Memorial; Mexico, at 10; India, at 12.

(26) See UN Survey of International Law, UN Doc. A/CN.4/1/Rev.l (UN Pub. 1948) V.l(l) at 34 (1949); Corfu Channel Case (Merits) ICJ Reports (1949) at 4 and 22. Trail Smelter Case,n. 17 above. In a 1978 communication the United States observed that ‘no state might claim to use the waters of an international river in such a way as to cause material injury to the interests of other states’. See United States notes to Canada and Mexico [1978] Digest of United States Practice in International Law at 1116–17, 1121–2; see also statements made by the United States in the General Assembly, UN. GAOR C.6 (764th mtg) (1962) at 158; Smith, State Responsibility,n. 13 above at 72. See also written statements submitted by states in connection with the Advisory Opinion on the Legality of Nuclear Weapons,n. 25 above; Birnie and Boyle,n. 10 above at 92; P. Sands, Principles of International Environmental Law, Vol. I (Manchester, 1995) at 186; Orrégo Vicuna,n. 9 above at 129–30.

(27) Brownlie,n. 9 above at 1; see also the dissenting opinion of Judge de Castro in the Nuclear Tests Cases, ICJ Reports (1974) at 253 and 388–9.

(28) J. B. Moore, International Arbitrations to which the United States has been a Party, Vol. II at 1964.

(29) Moore, International Arbitrations, n. 28 above at 4706.

(30) Moore, International Arbitrations, n. 28 above at 1964–6.

(31) See S. McCaffrey, Fifth Report on the ‘Law on the Non-Navigational Uses of International Watercourses’, Vol. II, Part I, YBILC (1989) at 113.

(32) n. 17 above.

(33) However, for the view that the case was decided ex aequo et bono rather than on the basis of law, see K. Zemanek, ‘General Course’,n. 8 above at 239.

(34) ICJ Reports (1949) at 4 and 22.

(35) Schachter, n. 22 above at 365; Birnie and Boyle,n. 10 above at 141; Brownlie, State Responsibility,n. 23 above at 152–5.

(36) ICJ Reports (1996) at 241, para 29; see also Case Concerning Gabčikovo-Nagymaros Project,n. 2 above para 112.

(37) n. 25 above.

(38) 24 ILR at 101 and 123.

(39) n. 38 above.

(40) 11 ILM 1972 at 1416, 1421, and 1466, UN DOC/CONF/48/14/Rev.l. The Stockholm Principles received the approval of the majority of states in the General Assembly. The resolutions were adopted by a majority of members of the UNGA with 116 voting in favour, none against, 10 abstaining, UNGA Res. 2997 (XXVIII) 1972. This principle has more recently been reaffirmed in Principle 2 of the Rio Declaration on Environment and Development, 31 ILM (1992) at 876. See also the endorsement of the principle in written statements submitted by states in connection with the General Assembly and WHO Advisory Opinions,n. 25 above.

(41) Memorandum of the Legal Bureau, Canadian Department for External Affairs, XXV CYBIL (1987) at 402; see also Statement made in the HC by the Canadian Secretary of State for External Affairs of 8 June 1972 in connection with damage caused to Canadian waters as a result of the Cherry Point Oil Spill. Canada again asserted that the applicable principles were those to be found in the Trail Smelter Case, 11 CYBIL (1973) at 333–4; Handl, 74 AJIL (1980) at 525–45.

(42) See oral proceedings, arguments by Sir Kenneth Keith (New Zealand), Verbatim Record at 174–5 and argument of the French counsel M. Perrin de Brichambaut, Verbatim Record, at 205, in New Zealand Ministry of Foreign Affairs,n. 7 above.

(43) See Hungarian Memorial, para 7.46 and 7.50,n. 3 above; Counter-Memorial of the Slovak Republic, para 9.69. See also Legality of the Threat or Use of Nuclear Weapons by a State (General Assembly Request), written observations by Solomon Islands, para 4.16; Dissenting Opinion of Judge Weeramantry in the 1995 Nuclear Tests Cases (New Zealand v. France) (1995) ICJ Reports at 246–7.

(44) Although the dispute was initially referred to an arbitral tribunal, it was ultimately settled by the parties, 8 ILM (1969) at 118.

(45) McCaffrey, ‘Fifth Report’, n. 31 above.

(46) Nuclear Tests Cases (1978) ICJ Pleadings, Vol. I at 304 and Vol. II, para 17.

(47) Vol. I, n. 46 above.

(48) See the replies of both Australia and New Zealand to the question by Judge Waldock as to whether all forms of pollution could be the legitimate basis of an action: Nuclear Tests Cases, (1978) ICJ Pleadings, Vol. I, at 524–6 and Vol. II at 429–31, respectively.

(49) See the joint dissent of Judges Dillard, Onyeama, Jiménez de Aréchaga, and Sir Humphrey Waldock, n. 19 above at 367. See also the dissenting opinion of Judge Sir Garfield Barwick, n. 19 above at 433. See also the 1995 Nuclear Tests Cases,n. 2 above. New Zealand argued that the French underground tests in Mururoa and Fangataufa Islands violated the rights of all members of the international community, including New Zealand, to be free from radioactive contamination of the marine environment of the South Pacific. In its judgment of 22 September 1995, the International Court ruled that the basis of its 1974 judgment in the Nuclear Tests Cases (New Zealand v. France) had not been affected as required by para 63 of that judgment, that it therefore lacked the competence to reopen the dispute which had been declared moot in 1974. That the new application was concerned with underground nuclear tests whilst the 1974 case was exclusively concerned with atmospheric nuclear tests. As a result the application was dismissed. However, in their dissent, judges Weeramantry, Koroma, and judge ad hoc Sir Geoffrey Palmer regarded the New Zealand claim as well founded in law, Nuclear Tests Cases,n. 2 above at 317, esp. at 347–9, and at 363 at 373, respectively.

(50) M. Mendelson, ‘State Acts and Omissions as Explicit or Implicit Claims’, in Mélanges M. Virally Le Droit International au Service de la Paix, de la Justice et du developpement (Paris, 1991) at 373–7.

(51) n. 2 above.

(52) Comité Interministeriel pour lʼlnformation, Livre Blanc sur les Experiments Nucléates (1973) cited in Lammers,n. 9 above at 324; see also the French reply to the Australian note of 3 January 1973, Nuclear Tests Cases (1978) ICJ Pleadings, Vol. I at 28.

(53) Text in New Zealand Ministry of Foreign Affairs and Trade, French Nuclear Testing in the South Pacific (Wellington, 1996) at 207–8.

(54) 961 UNTS at 187.

(55) 18 ILM (1979) at 902–30.

(56) Cited in Lammers,n. 9 above at 223; ILA, Legal Aspects of the Conservation of the Environment (1982), 60th Conference at 157–65.

(57) Klein, Umweltschutz in Volkerrechtlichen Nachbarrecht (Berlin, 1976) at 62, cited in Lammers,n. 9 above at 222.

(58) Lammers,n. 9 above at 214.

(59) AP Chambre 1972–3, 2 May 1973 at 1625.

(60) Memorial of the Republic of Hungary,n. 7 above, para 7.45 at 219; Counter Memorial of the Slovak Republic, n. 43 above, para 9.69–9.72.

(61) Report of the UN Conference on the Human Environment, UN Doc./CONF/48/14/Rev.l, 11 ILM (1972), at 1416, 1421, 1466. See also Principle 2 of the Rio Declaration on Environment and Development, n. 40 above at 876; Principle 1(a) of the Non-Legally Binding Authoritative Statement of Principles for a Global Consensus on Management, Conservation, and Sustainable Development of all Types of Forests, 31 ILM (1992), 881 at 883.

(62) 112 states voted in favour of the Resolution with none against. It is significant that for the avoidance of doubt, the United States and Canada found it necessary to state that Principle 21 did not in any way undermine the pre-existing responsibility of states under general international law: UN Doc.A/CONF.48/14/Rev. 1 at 64–6; the Helsinki Final Act also restates the responsibility of states in language not dissimilar to Principle 21, 14 ILM (1975) at 1292–1307. Principle 21 was confirmed in UNGA Res. 2996 (XXVII) of 1972.

(63) Preamble to the 1979 ECE Convention on Transboundary Air Pollution, 1302 UNTS at 217; Vienna Convention for the Protection of the Ozone Layer, 19 UKTS Cm 977 (1990); Kuwait Regional Convention for Co-operation in the Protection of the Marine Environment, 1140 UNTS at 133; Articles 4(1), 5, 7, and 8 of the 1976 Barcelona Convention, 15 ILM (1976) at 290; Article 194 of the 1982 Law of the Sea Convention, 21 ILM (1982) at 1261.

(64) Institute of International Law, Air Pollution Across Frontiers, n. 16 above at 205, draft Article 5. See also statement by the Special Rapporteur, Nascimento e Silva, at 203; ILA Committee on Long-Distance Air Pollution, n. 16 above at 391; American Law Institute, Third Restatement (St Paul, Minnesota, 1987), Vol. II at 103.

(65) I. Brownlie, Principles of Public International Law, 5th edn. (Oxford, 1998) at 284.

(66) See Schachter, n. 22 above at 365; See also Zemanek,n. 8 above.

(67) The International Court of Justice in its judgment in the Nicaragua Case observed that for a rule of customary law to come into existence, absolute uniformity is not required, as long as there is cogent evidence to suggest that divergent practices are instances of breach of a rule rather than the affirmation of a new emergent norm, see above n. 19 at 98, para 186.

(68) Brownlie, n. 65 above at 437; Jiménez de Aréchaga, ‘International Responsibility’, in M. Sørensen (ed.), Manual of Public International Law (London, 1968) at 534–7; R. Higgins, ‘General Course on Public International Law’, 230 Recueil des Cours (1991) at 199; Schachter, above n. 22 at 203; R. Ago, Third Report on State Responsibility, draft Article 1, YBILC (1971), Vol. II (Part I) at 205–14; Phosphates in Morocco Case (Preliminary Objections), 1938 PCIJ Series A/B, No. 74 at 28; Chorzow Factory Case (Merits) PCIJ Series A, No. 9 at 21 and No. 17 at 29; Reparations Case, ICJ Reports (1949) at 184.

(69) Brownlie, n. 65 above at 433; see also Brownlie, above n. 22 at 37; Schachter, n. 21 at 203; Jiménez de Aréchaga, (in Sorensen, ed.), n. 68 above at 531 and 534–5.

(70) H. Lauterpacht (ed.), Oppenheim's International Law, Vol. I, 8th edn. (London, 1955) at 343; (see also 9th edn. ed. Jennings and Watts (London, 1992) at 509; H. Lauterpacht, ‘Régies Générates Du Droit De La Paix’, 62 Recueil des Cours (1937), Vol. IV at 359–64; C. Eagleton, Responsibility of States in International Law (New York, 1928) at 209.

(71) Brownlie, State Responsibility,n. 23 above at 41–4.

(72) See Cheng, General Principles of Law as Applied by International Tribunals (London, 1953) at 218–32. Most of the cases usually cited in support of the fault principle were concerned with breaches of obligations owed to aliens, an area of the law where it has always been accepted that responsibility can only be imposed on a state on account of fault or want of care on its part. See the Salvador Prats Case, III RIAA, at 2886–93; The Russia Indemnity Case (1912) 1 HCR, at 532–43; Home Missionary Society Case, VI RIAA at 42–4.

(73) Birnie and Boyle,n. 10 above at 144; Handl, 74 AJIL (1980) at 535; Schachter, n. 22 above at 368–9; OECD, Legal Aspects of Transfrontier Pollution (Paris, 1979) at 386; Smith,n. 13 above at 144.

(74) ALI, Restatement, n. 64 above; Article 194 of the Law of the Sea Convention requires states to ‘control pollution of the marine environment from any source, using for this purpose the best practicable means at their disposal and in accordance with their capabilities’, 21 ILM (1982) at 1261.

(75) OJ NOC 22230/8/80. Other treaty provisions employing the word ‘endeavour’ are to be found in the field of marine pollution. These include Article 6(8) of the 1974 Helsinki Convention on the Baltic Sea, 13 ILM (1974) at 546; see also Articles 204 and 207 of the 1982 Law of the Sea Convention, 21 ILM (1982) at 1261; 1140 UNTS at 133.

(76) Article XIV of the Air Quality Agreement between the United States and Canada (1991), Can. T.S. No. 3.

(77) See generally Chapter 2. Canadian practice in other contexts also supports the due diligence standard. See Legal Memorandum dated 18 February 1978 issued by the Canadian Government's Department for External Affairs. See Memorandum of the Legal Bureau, Canadian Department for External Affairs, XXV CYBIL (1987) at 402.

(78) Committee on Legal Aspects of Long-Distance Pollution, 61st Conference, n. 16 above.

(79) n. 16 above. The earlier draft article had provided that' … states shall be under a duty to ensure that their activities or those conducted within their jurisdiction or under their control cause no transboundary air pollution'. For criticism of the provision, see contributions by Crawford, Dinstein, and Schachter. Referring to the Draft Article, Schachter noted that there were various ways of tackling the problem, e.g. a duty to abate and take all reasonable steps to prevent pollution (at 197); Crawford, agreeing with Schachter, noted that an absolute provision such as that proposed in Article 2 was unlikely to be effective (at 213); Dinstein proposed that Article 2 should be amended by adding the phrase ‘take all appropriate and effective measures’ (at 213); Institute of International Law, Air Pollution Across Boundaries (1987), Vol. 62, Part II.

(80) Rio Declaration on Sustainable Development and Agenda 21, 31 ILM (1992) at 874.

(81) Counter-Memorial of the Republic of Hungary, Vol. I, para 6.134.

(82) Counter-Memorial of the Slovak Republic,n. 6 above.

(83) 33 Ann. IDI (1927) (Part III) at 331 (original in French); Blomeyer-Bartenstein, ‘Due Diligence’, in R. Bernhardt (ed.), Encyclopedia of Public International Law (1992) Vol. 1 at 1112; Higgins, ‘General Course’, n. 68 above (Part V) at 207; Short v. Republic of Iran (Iran-United States Claims Tribunal), 82 ILR at 149 and 160–1; Hostages Case, ICJ Reports (1980) at 3 and 30; Smith, State Responsibility,n. 13 above at 36–2.

(84) Moore, International Arbitrations, n. 28 above at 2886–93. See also the Alabama Arbitration, Moore, Arbitrations, Vol. I, at 494–682; but see Montijo Case (1874) (UnitedStates v. Colombia), Moore, Arbitrations, Vol. II, at 1421–44, where the tribunal did not pay regard to the difficulties that the state had encountered in discharging its obligation.

(85) See the Alabama Arbitration, n. 28 above at 494–682.

(86) IV RIAA, at 60; see also the decision of the same Commission in the Laura Mecham Case, IV RIAA at 440–3.

(87) Counter-Memorial of the Republic of Hungary, n. 4 above, para 6.136.

(88) Hungarian Memorial,n. 7 above, paras 8.01–8.52; n. 4 above; D. M. Dupuy, ‘Due Diligence in the International Law of Liability’, in OECD, Legal Aspects of Transfrontier Pollution (Paris, 1977) at 369–79.

(89) Verbatim Record CR 95/20, Public Sitting of 12 September 1995 at 33.

(90) Higgins, ‘General Course’, n. 68 above at 207; Brownlie, Principles, n. 65 above at 527; n. 88 above; M. M. Whiteman, Digest of International Law (Washington, 1965), Vol. VIII at 697; Smith,n. 13 above at 40; Dupuy, n. 88 above at 369–74; Eagleton, Responsibility of States, n. 70 above at 89–90.

(91) It had been observed that the contemporary view would seem to be a hybrid of the two approaches: the diligence of the state will be considered in light of its particular capacities and practices. If, however, its conduct falls below an international minimum standard, responsibility will nevertheless lie, Smith,n. 13 above at 4; see also Brownlie, Principles, n. 65 above at 527–8.

(92) n. 83 above.

(93) P. Sands, ‘International Law in the Field of Sustainable Development’, 65 BYBIL (1994) at 303–18.

(94) ILC's Work on the Law of the Non-navigational Uses of International Watercourses, commentary to Article 7, also include individual comments of members of the ILC; see also Counter-Memorial of the Slovak Republic, 5 December 1994, vol. 1 at 255–6.

(95) n. 63 above.

(96) See generally New Zealand arguments in the 1995 Nuclear Test Cases, New Zealand Ministry of Foreign Affairs and Trade, French Nuclear Testing in the Pacific,n. 7 above; Memorial of the Republic of Hungary,n. 7 above at para 6.57–6.69.

(97) Sands, n. 93 above at 345; Birnie and Boyle,n. 10 above at 95–8; L. Gundling, ‘The Status in International Law of the Principle of Precautionary Action’, 5 International Journal of Estuarine and Coastal Law (1990) at 23; D. Freestone, ‘The Precautionary Principle’, in R. Churchill and D. Freestone (eds.), International Law and Global Climate Change (London, 1991) at 21; E. Hey, ‘The Precautionary Concept in Environmental Policy and Law’, 4 Georgetown International Environmental Law Review (1992) at 303.

(98) n. 97 above.

(99) I. Brownlie, ‘General Course’, above n. 10.

(100) The formulation of the duty to carry out environmental impact assessment in the UNEP Principles clearly indicates that whether or not the duty is relevant in a particular case will depend on the nature of the activity as well as the likelihood and seriousness of harm; UNEP Guidelines of 1987 on ‘Goals and Principles of Environmental Impact Assessment’. UNEP Resolution GC 14/2.5.

(101) Nuclear Tests Cases (New Zealand v. France) Verbatim Record, CR 95/20; see also dissenting opinion of Judge ad hoc Sir Geoffrey Palmer (1995), ICJ Reports at 441.

(102) CR 95/20 at 26–7.

(103) See argument of Mr Mackay, Oral Proceedings, CR 95/20 at 37. New Zealand's argument was sympathetically endorsed by Judge Weeramantry in his dissenting opinion (1995) ICJ Reports at 342.

(104) Arguments of M. Perrin de Brichambaut, translation of oral arguments in French Nuclear Testing in the Pacific, aboven. 7 at p. 205; see also arguments by Counsel for Slovakia in the Gabčikovo-Nagymaros Case, Mr McCaffery, CR 97/9 at 37.

(105) Hungarian Memorial,n. 7 above at para 6.57–6.69, and Counter-Memorial of the Republic of Hungary, n. 4 above, para 4.20–4.27.

(106) See arguments by Mr McCaffery, CR 97/9 at 34.

(107) UNCED Prepcom, UN DOC.A/CONF.151/PC/WGll/Misc.4 (1991).

(108) See arguments of Mr McCaffery, Counsel for Slovakia, Verbatim record, 97/9 at 37 and Counsel for France, M. Perrin de Brichambaut, n. 104 above, in the 1995 Nuclear Tests Cases.

(109) Arguments of Mr McCaffery, Verbatim Record CR97/9 at 35.

(110) Nuclear Tests Cases (1978) ICJ Pleadings, at 14; see also the dissenting opinion of Judge Sir Garfield Barwick, ICJ Reports (1974) at 432–3.

(111) Comité Interministériel pour lʼlnformation, n. 52 above at 20; see also the arguments of M. Perrin de Brichambaut, 1995 Nuclear Tests Cases, n. 104 above at 207; also generally Chapter 4.

(112) See K. Sachariew (1990), Nethers Intl. Law Rev., at 193; Schachter, n. 22 above at 366.

(113) See, for instance, Principle 15 of the Rio Declaration on the Environment and Development, n. 40 above at 31; Article 3 (3) of the UN Framework Convention on Climate Change, 31 ILM (1992) at 849; Maastricht Treaty on European Union, 31 ILM (1992) at 253, Art. 130r(2). For a general account, see Gundling, above n. 97; Birnie and Boyle,n. 10 above; Sands, n. 93 above; Hey, n. 97 above; Freestone, n. 97 above; Brownlie, ‘General Course’,n. 10 above.

(114) See Article 5 of the 1979 ECE Convention, n. 63 above; Article 1 para 2 of the 1985 Vienna Convention on the Protection of the Ozone Layer, n. 63 above (significant deleterious effects); see also Article 206 of the 1982 UN Law of the Sea Convention (substantial pollution, significant and harmful changes), n. 63 above; Article 3 of the 1980 Memorandum of Intent (significant risk of pollution), 20 ILM (1981) at 690; Agreement between the United States and Mexico on the Protection of the Environment in the Border Area, 22 ILM (1983) at 1025; Preamble to the 1991 Air Quality Agreement between the United States and Canada (significant harm) (1991) Can. T.S. No. 3.

(115) See para 1 of the UNEP Goals and Principles of Environmental Impact Assessment (significant effects on the environment) in UNEP, Environmental Law Guidelines and Principles, No. 9 (1987) at 1; and also Principle E of the OECD Principles Concerning Transfrontier Pollution (significant risk of transfrontier pollution), in OECD (1979) at 106–12. See also Art. 2(1) of the Convention on Environmental Impact Assessment in a Transboundary Context (Espoo), 30 ILM (1991) at 802.

(116) The WCED employs the term substantial to denote harm that is significant, i.e. not minor, see Our Common Future (Oxford, 1987) at 348–51; McCaffrey also uses the term ‘appreciable’ harm to denote the quantitative character of harm yielding liability. In each case the harm prohibited should not be trivial or inconsequential: there must be an actual impairment of use, injury to health or property, or a detrimental effect upon the ecology; see McCaffrey, Fourth Report on the Law of Non-Navigational Uses of International Watercourses, YBILC (1988), Vol. II (Part II) at 205–38.

(117) Brownlie, in Teclaff and Utton (eds.),n. 9 above; Brownlie, General Course,n. 10 above; Hurrell and Kingsbury,n. 10 above at 25–6; Orrégo Vicuna,n. 10 above at 124 and 126–7; Schachter, n. 22 above at 380–1; C. Gray, Judicial Remedies in International Law (Oxford, 1988) at 210 and 223–4.

(118) See the arguments of New Zealand in 1974 Nuclear Tests Cases, ICJ Pleadings, Nuclear Tests Cases, Vol. II, at 204 (para 191); 1995 Nuclear Tests Cases, Registrar's letter of 21 August 1995; see also Application for Permission to Intervene under the terms of Article 62 of the Statute submitted by the Government of Australia, 23 August 1995, paras 20–5 and 33; see also Application for Permission to Intervene submitted on behalf of the Governments of Samoa, Solomon Islands, Marshall Islands, and Federated States of Micronesia, paras 19 and 20,n. 7 above; Memorial of the Republic of Hungary,n. 7 above, para 6.63; Dissenting Opinion of Judge Weeramantry, in Legality of the Use by a State of Nuclear Weapons in Armed Conflict, 1996 ICJ Reports; Separate Opinion in the Gabčikovo Nagymaros Case,n. 2 above at 25; Schachter, n. 22 above at 381; Orrégo Vicuna,n. 9 above at 124 and 136; Smith, State Responsibility,n. 13 above at 103. See also Draft Article 19 of the Draft Articles provisionally adopted by the ILC, YBILC (1979) Vol. II (Part II) at 92; C. Chinkin, Third Parties in International Law (Oxford, 1993) at 93; M. Ragazzi, n. 7.

(119) A. Boyle, in R. R. Churchill and D. Freestone (eds.), International Law and Global Climate Change (London, 1991) at 7 and 12; J. Charney, 10 Mich. J of Intl. Law (1989) at 57.

(120) Hurrell and Kingsbury,n. 10 above at 7–8; H. Bull, The Anarchical Society: A Study of Order in World Politics (London, 1977) Part 3; J. Schneider, World Public Order of the Environment (London, 1979) at 6.

(121) Indeed, with the exception of the right to anticipatory self-defence there is almost no discussion of international remedies in cases of threatened breach. The general absence of such remedies is noted by Gray, n. 117 above at 12.

(122) Principle 15, 31 ILM (1992) at 874 at 879; See also Article 3 of the Framework Convention on Climate Change, 31 ILM (1992), at 849; Maastricht Treaty on European Union, 31 ILM (1992) at 253, Art. 130r (2).

(123) See New Zealand arguments in the 1995 Nuclear Test Cases, New Zealand Documents, above n. 7, para 105; Memorial of the Republic of Hungary, above n. 105, D. Freestone, in Churchill and Freestone, n. 119 above at 21–2; Gundling, n. 97 above at 23–30; Birnie, in Hurrell and Kingsbury,n. 10 above at 52.

(124) Memorial of the Republic of Hungary, n. 105 above; see also New Zealand arguments, CR 95/20 at 35–7.

(125) Sands, n. 93 above; O. Mclntyre and T. Mosedale, ‘The Precautionary Principle as a Norm of Customary International Law’, 2 JEL (1997).

(126) Brownlie, ‘General Course’,n. 10 above, and Principles, n. 65 above at 286.

(127) See arguments of M. Perrin de Brichambaut,n. 7 above at 205.

(128) Birnie anci Boyle,n. 10 above at 98.

(129) In her Hague Academy lectures Higgins concedes that although the status of a human right to a safe environment is uncertain, it is probably in a state of evolution: ‘General Course’, n. 68 above at 148. Advocates of a distinct human right to a clean environment rely on several international instruments as supporting their position, in particular Principle 1 of the Stockholm Declaration which provides that ‘Man has the fundamental right to freedom, equality, and adequate conditions of life, in an environment of a quality that permits a life of dignity and well-being’; see also Article 24 of the African Charter on Human and Peoples' Rights, (1982) 21 ILM at 58: this recognizes the right of all peoples to ‘a generally satisfactory environment favourable to their development’. The Additional Protocol to the American Convention on Human Rights in the Area of Economic, Social and Cultural rights (Protocol of San Salvador) (1989) 28 ILM (not yet in force), Article 11 provides that: ‘1. Everyone shall have the right to live in a healthy environment and to have access to basic public services’. In 1987, the WCED included the following in their proposed legal principles for Environmental Protection and Sustainable Development: ‘All human beings have a fundamental right to an environment adequate for their health and well-being’ (n. 116 above).

(130) Henkin, n. 11 above at 242.

(131) R. Higgins, International Law and How We Use It (Oxford, 1994) at 105.

(132) Proponents of such a right argue that the right inheres in individuals as well as in all states. On this reasoning, all states have a right to insist on the observance of such environmental obligations. See Kiss,n. 9 above at 199–201; Pathak, in Brown Weiss (ed.),n. 9 above at 205–43; Cancado Trindade, in Brown Weiss (ed.)n. 9 above at 244 at 291.

(133) Higgins, ‘General Course’, n. 68 above at 146; Henkin, ‘General Course’ n. 11 above at 247; A. Boyle, ‘The Role of International Human Rights Law in the Protection of the Environment’, in Boyle and Anderson (eds.), n. 15 above at 43; J. G. Merrills, ‘Environmental Protection and Human Rights: Conceptual Aspects’, in Boyle and Anderson (eds.), n. 15 above at 25; Hurrell and Kingsbury,n. 10 above at 27; Birnie and Boyle,n. 10 above at 191.

(134) Henkin, n. 11 above at 247.

(135) UN Commission on Human Rights, Sub-Commission on Prevention of Discrimination and Protection of Minorities, Human Rights and the Environment, Final Report of the Special Rapporteur, UN Doc. E/CN.4/SUB.2/1994/9 (6 July 1994) at 74.

(136) A. Boyle, n. 133 above at 63–5.

(137) See A. Boyle, n. 133 above at 53.

(138) E. Brown Weiss, Our Rights and Obligations to Future Generations for the Environment', 84 AJIL (1990) at 198.

(139) C. Redgwell, ‘Life, The Universe and Everything: A Critique of Anthropocentric Rights’ in Boyle and Anderson (eds.), n. 15 above at 71.

(140) Birnie, in Hurrell and Kingsbury,n. 10 above at 51–79; see also Gundling, 84 AJIL (1990), at 207 and 210–11.

(141) Art. 2 of the 1974 Nordic Convention on the Protection of the Environment, 13 ILM (1974) at 546 (in force 5 October 1976); OECD Secretariat, Report on Equal Access in OECD Member Countries, in OECD, Legal Aspects of Transfrontier Pollution (Paris, 1977) at 54; Brussels Convention on Jurisdiction and Judgments in Civil and Commercial Matters, 8 ILM (1968) at 229.

(142) It is well established that, in certain circumstances, a number of treaties formulated in the same way may serve as evidence that a particular rule has assumed the status of general international law. See North Sea Continental Shelf Cases, ICJ Reports (1969) at 41, but note the caution sounded by the Court that whether or not treaty norms had passed into the corpus of general international law was not to be lightly presumed; The Wimbledon Case (1923), PCIJ, Ser. A, No. 1 at 25; Panevezys-Saldutiskis Railway Case, PCIJ, Ser. A/B, No. 76 at 51–2, per Judge Ehrlich; The Nottebohm Case, ICJ Reports (1955) at 22–3; R. R. Baxter, ‘Treaties as Custom’, 129–1 Recueil des Cours (1970) at 75–91.