International Environmental Law — Stockholm, Rio, Paris Agreements

International environmental law is among the youngest and most rapidly developing branches of international law. It rests on the recognition that pollution and ecological degradation generated within one State produce consequences in others, and that some environmental problems — climate change, ozone depletion, loss of biological diversity, marine pollution — cannot be addressed by States acting individually. The discipline traces its modern beginning to the United Nations Conference on the Human Environment held at Stockholm in June 1972 and has been consolidated in two further great conferences: the United Nations Conference on Environment and Development at Rio de Janeiro in June 1992 and the twenty-first Conference of the Parties to the UN Framework Convention on Climate Change at Paris in December 2015. The chapter that follows traces the architecture from Stockholm to Paris, sets out the core principles of the field, and examines how the Indian Supreme Court has incorporated these principles into the construction of Articles 14, 21, 47, 48-A and 51-A(g) of the Constitution. The wider canvas of these International Law for Judiciary notes sets the institutional and source-of-law context.

The chapter that follows opens with the customary-law foundations of the discipline, surveys the landmark conferences and instruments, sets out the core principles (sustainable development, precautionary principle, polluter-pays principle, common but differentiated responsibilities), and closes with the reception of these principles in Indian constitutional and administrative practice.

The customary-law foundations — the no-harm rule

The earliest layer of international environmental law is customary. It rests on the rule, traceable to the Trail Smelter arbitration between Canada and the United States (1938 and 1941, 3 RIAA 1905), that no State has the right to use or permit the use of its territory in such a manner as to cause injury by fumes in or to the territory of another or the properties or persons therein, when the case is of serious consequence and the injury is established by clear and convincing evidence. The principle was extended by the International Court in Corfu Channel (1949) ICJ Reports 4, where the Court read into the territorial sovereignty of every State an obligation not knowingly to allow its territory to be used for acts contrary to the rights of other States. The Court reaffirmed the obligation in its Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons (1996) ICJ Reports 226, where it declared the 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 to be part of the corpus of international law relating to the environment. The customary nature of the no-harm rule is examined in the broader chapter on customary international law and general principles.

Principle 21 of the Stockholm Declaration of 1972 codified the rule in famous terms: 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 of areas beyond the limits of national jurisdiction. Principle 2 of the Rio Declaration of 1992 carried the same formulation forward, with the addition of a reference to developmental policies. Article 192 of the United Nations Convention on the Law of the Sea, 1982 — examined in the chapter on the UNCLOS regime relevant to India — generalised the principle to the marine environment by providing that States have the obligation to protect and preserve the marine environment, with Article 194 imposing a duty to take all measures necessary to prevent, reduce and control marine pollution.

The Stockholm Conference, 1972

The United Nations Conference on the Human Environment, held at Stockholm from 5 to 16 June 1972, was convened by General Assembly resolution 2398 (XXIII) of 1968. It was the first global intergovernmental conference dedicated to the environment. It produced three principal outputs. First, the Stockholm Declaration of twenty-six principles, of which Principle 21 has acquired customary force as set out above and Principle 22 invited States to develop further the international law regarding liability and compensation for victims of pollution and other environmental damage caused by activities within their jurisdiction or control to areas beyond their jurisdiction. Second, an Action Plan with 109 recommendations covering settlement, environmental aspects of natural resources management, identification and control of pollutants, and educational, informational, social and cultural aspects of environmental issues. Third, an institutional output — the United Nations Environment Programme (UNEP), established by General Assembly resolution 2997 (XXVII) of 15 December 1972 with its headquarters at Nairobi. UNEP has been the institutional engine for the major multilateral environmental agreements concluded since 1972, including the 1985 Vienna Convention for the Protection of the Ozone Layer, the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, the 1992 Convention on Biological Diversity and the 1989 Basel Convention on the Control of Transboundary Movements of Hazardous Wastes — all built on the broader institutional architecture mapped in the chapter on the UN system and the chapter on specialised UN agencies.

The Indian delegation to Stockholm was led by Prime Minister Indira Gandhi, whose celebrated address at the Plenary linked poverty and environmental degradation in terms that prefigured the later concept of sustainable development. Her formulation — that poverty is the worst form of pollution — has been quoted in successive Indian environmental judgments and shaped the constitutional incorporation of environmental obligations through the 42nd Amendment, 1976, which inserted Article 48-A into the Directive Principles and Article 51-A(g) into the Fundamental Duties.

The Rio Conference, 1992

The United Nations Conference on Environment and Development, held at Rio de Janeiro from 3 to 14 June 1992 (the so-called Earth Summit), was convened by General Assembly resolution 44/228 of 1989. It produced five principal outputs. First, the Rio Declaration on Environment and Development of twenty-seven principles, including the Principle 2 restatement of Stockholm Principle 21, the Principle 3 articulation of inter-generational equity and the Principle 15 articulation of the precautionary approach. Second, Agenda 21, a four-hundred page action programme covering virtually every dimension of the human-environment relationship. Third, the Statement of Principles for a Global Consensus on the Management, Conservation and Sustainable Development of All Types of Forests. Fourth, the United Nations Framework Convention on Climate Change (UNFCCC), opened for signature at Rio and entered into force on 21 March 1994. Fifth, the Convention on Biological Diversity (CBD), also opened for signature at Rio and entered into force on 29 December 1993. India ratified both Conventions; it is also a party to the 2000 Cartagena Protocol on Biosafety to the CBD and the 2010 Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization. The interaction with the regional-trade architecture is taken up in the chapter on regional organisations — SAARC, ASEAN, EU, AU and the trade-environment interface in the chapter on the WTO and international trade law.

Two follow-on instruments have shaped the post-Rio period. The Kyoto Protocol to the UNFCCC, adopted on 11 December 1997 and entered into force on 16 February 2005, set quantified emission reduction commitments for the developed-country (Annex I) Parties for the first commitment period (2008-2012) and operationalised three flexibility mechanisms — joint implementation under Article 6, the Clean Development Mechanism (CDM) under Article 12 (in which Indian projects participated extensively) and emissions trading under Article 17. The Doha Amendment of 2012 set a second commitment period (2013-2020). The Paris Agreement, considered separately below, replaced this top-down architecture with a bottom-up nationally-determined-contribution model.

The Paris Agreement, 2015

The Paris Agreement, adopted at the twenty-first Conference of the Parties to the UNFCCC on 12 December 2015 and entered into force on 4 November 2016, is the operative climate-change instrument. Its central provisions are set out in Articles 2, 3 and 4. Article 2 sets the long-term temperature goal — to hold the increase in the global average temperature to well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 degrees Celsius above pre-industrial levels — together with goals on adaptation and on making finance flows consistent with a pathway towards low greenhouse-gas emissions and climate-resilient development. Article 3 introduces the concept of nationally determined contributions (NDCs), under which each Party prepares, communicates and maintains successive contributions reflecting its highest possible ambition, taking into account common but differentiated responsibilities and respective capabilities in the light of different national circumstances. Article 4 sets the substantive obligation to communicate an NDC every five years and to pursue domestic mitigation measures with the aim of achieving the objectives of those contributions.

India submitted its Intended Nationally Determined Contribution on 2 October 2015 and ratified the Agreement on 2 October 2016. India's NDC commits to a reduction in the emissions intensity of GDP by 33 to 35 per cent by 2030 from 2005 levels, an increase in the share of non-fossil-fuel-based power generation capacity to about 40 per cent by 2030, and the creation of an additional carbon sink of 2.5 to 3 billion tonnes of CO2 equivalent through additional forest and tree cover by 2030. India's revised NDC of August 2022 increased the emissions-intensity reduction target to 45 per cent and the non-fossil power-generation capacity target to 50 per cent by 2030. The wider treaty-law framework within which the Paris Agreement operates — including the rules on consent to be bound, reservations and entry into force — is examined in the chapter on treaties — formation, validity and termination.

Sustainable development

Sustainable development is the conceptual bridge between environmental protection and the right to economic and social development. The phrase was crystallised by the Brundtland Commission's report Our Common Future of 1987 — development that meets the needs of the present without compromising the ability of future generations to meet their own needs. The principle entered the Rio Declaration as Principle 4: 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. The International Court adverted to the concept in the Gabcikovo-Nagymaros case (Hungary v. Slovakia) (1997) ICJ Reports 7, observing that new norms and standards developed in the field of environmental law had been formulated and that such new norms had to be taken into consideration not only when States contemplated new activities but also when continuing with activities begun in the past. The Indian Supreme Court adopted sustainable development as part of Indian environmental law in Vellore Citizens Welfare Forum v. Union of India (1996) 5 SCC 647, holding that sustainable development as a balancing concept between ecology and development had been accepted as part of customary international law. The 2015 Sustainable Development Goals (SDGs) — Agenda 2030 adopted by the General Assembly through resolution 70/1 — operationalise the concept across seventeen goals and 169 targets.

The precautionary principle

The precautionary principle was articulated in Principle 15 of the Rio Declaration: 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. The principle's significance lies in its reversal of the conventional evidentiary architecture of the no-harm rule. The conventional rule required clear and convincing evidence of damage before liability could be engaged; the precautionary principle requires preventive action before scientific certainty is established. The principle has been progressively absorbed into multilateral environmental agreements, including Article 3(3) of the UNFCCC and Article 1 of the Cartagena Protocol on Biosafety. The Indian Supreme Court accepted the precautionary principle as part of Indian environmental law in Vellore Citizens Welfare Forum (1996), holding that environmental measures by the State Government and the statutory authorities must anticipate, prevent and attack the causes of environmental degradation; that where there are threats of serious or irreversible damage, lack of scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation; and that the onus of proof is on the actor or the developer or industrialist to show that the action is environmentally benign. The principle was reaffirmed in A.P. Pollution Control Board v. M.V. Nayudu (1999) 2 SCC 718.

The polluter-pays principle

The polluter-pays principle was first articulated by the Organisation for Economic Co-operation and Development in 1972 as a means of internalising the costs of pollution prevention and control. It found expression in Principle 16 of the Rio Declaration: national authorities should endeavour to promote the internalisation of environmental costs and the use of economic instruments, taking into account the approach that the polluter should, in principle, bear the cost of pollution, with due regard to the public interest and without distorting international trade and investment. The Indian Supreme Court accepted the principle in Indian Council for Enviro-Legal Action v. Union of India (1996) 3 SCC 212 (the Bichhri case) and in Vellore Citizens Welfare Forum (1996), holding that the absolute liability for harm to the environment extends not only to compensating the victims of pollution but also to the cost of restoring the environmental degradation; remediation of the damaged environment is part of the process of sustainable development and as such polluters are liable to pay the cost to the individual sufferers as well as the cost of reversing the damaged ecology. The principle finds further expression in M.C. Mehta v. Union of India (1987) 1 SCC 395 (the Oleum Gas Leak case), where the Supreme Court formulated the doctrine of absolute liability for hazardous-industry operators.

Common but differentiated responsibilities (CBDR)

Common but differentiated responsibilities was articulated in Principle 7 of the Rio Declaration: in view of the different contributions to global environmental degradation, States have common but differentiated responsibilities. The developed countries acknowledge the responsibility that they bear in the international pursuit of sustainable development in view of the pressures their societies place on the global environment and of the technologies and financial resources they command. The principle is expressly incorporated in Article 3(1) of the UNFCCC, which directs the Parties to protect the climate system on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities. The principle is the conceptual basis for the Annex I/non-Annex I distinction in the UNFCCC and for the Kyoto Protocol's allocation of emission-reduction commitments only to Annex I Parties. The Paris Agreement preserves the principle but reformulates it as common but differentiated responsibilities and respective capabilities, in the light of different national circumstances — a phrasing that recognises evolving capabilities and shifts away from rigid Annex-based bifurcation.

Other multilateral environmental agreements

The post-Stockholm period has produced an extensive body of multilateral environmental agreements. The 1971 Ramsar Convention on Wetlands of International Importance especially as Waterfowl Habitat protects wetlands and their ecological functions. The 1972 London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter, with its 1996 Protocol, regulates ocean dumping. The 1973 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) protects threatened species through trade controls. The 1979 Geneva Convention on Long-Range Transboundary Air Pollution and its protocols address acid rain and related transboundary air pollution. The 1985 Vienna Convention on the Protection of the Ozone Layer and the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer (with its successive amendments — London 1990, Copenhagen 1992, Montreal 1997, Beijing 1999 and Kigali 2016) constitute the most successful multilateral environmental regime to date, having effectively phased out chlorofluorocarbons globally. The 1989 Basel Convention regulates transboundary movements of hazardous wastes; the 1998 Rotterdam Convention regulates the prior informed consent procedure for hazardous chemicals and pesticides; the 2001 Stockholm Convention on Persistent Organic Pollutants regulates twelve and now more categories of persistent organic pollutants. The 2013 Minamata Convention on Mercury, named after the Japanese city devastated by methylmercury poisoning, regulates anthropogenic emissions of mercury.

The Indian dimension — constitutional and statutory framework

India's constitutional response to environmental concern was set in train by the 42nd Amendment, 1976, which inserted Article 48-A into the Directive Principles ("the State shall endeavour to protect and improve the environment and to safeguard the forests and wild life of the country") and Article 51-A(g) into the Fundamental Duties ("to protect and improve the natural environment including forests, lakes, rivers and wild life, and to have compassion for living creatures"). The Indian Supreme Court has read the right to a clean environment into Article 21's protection of the right to life — the line of cases beginning with Subhash Kumar v. State of Bihar (1991) 1 SCC 598. The substantive statutory framework comprises the Water (Prevention and Control of Pollution) Act, 1974, the Air (Prevention and Control of Pollution) Act, 1981, the Environment (Protection) Act, 1986 (enacted under Article 253 of the Constitution to give effect to the decisions taken at the Stockholm Conference), the Public Liability Insurance Act, 1991, the National Green Tribunal Act, 2010 and the Compensatory Afforestation Fund Act, 2016. The deeper Indian-constitutional account is in the chapter on the Indian Constitution and international law; the broader account of how unincorporated treaties operate in Indian courts is in the chapter on the implementation of international treaties in Indian courts.

The reception of international principles in Indian courts

The Indian Supreme Court has consistently used international environmental principles as aids to construction of domestic environmental law. Vellore Citizens Welfare Forum v. Union of India (1996) 5 SCC 647 is the leading authority. The Court accepted that the precautionary principle and the polluter-pays principle had become part of customary international law and that, since the rules of customary international law that are not contrary to municipal law are deemed to have been incorporated in domestic law, these principles had become part of Indian environmental law. The Court directed the closure of polluting tanneries discharging untreated effluent into agricultural land in Tamil Nadu and constituted a Loss of Ecology Authority to compute and recover compensation. The same approach was applied in M.C. Mehta v. Union of India (1996) 4 SCC 750 (the Taj Trapezium case), in which the Court ordered industries within the Taj Trapezium Zone to switch to natural gas or close down on the basis of the precautionary principle, and in M.C. Mehta v. Kamal Nath (1997) 1 SCC 388 (the Span Motels case), in which the Court applied the public-trust doctrine to set aside a lease of public land to a private hotel that had encroached on a riverbed.

In T.N. Godavarman Thirumulpad v. Union of India (1997) 2 SCC 267 — the continuing-mandamus case on forest conservation — the Court extended its supervision to the implementation of the Forest (Conservation) Act, 1980, and has issued hundreds of orders shaping the practical operation of forest conservation, mining regulation and wildlife protection. In the Goa Foundation mining cases ((2014) 6 SCC 590; (2018) 4 SCC 218), the Court applied the polluter-pays and inter-generational-equity principles to require disgorgement of the proceeds of illegal mining. The Indian Supreme Court has also recognised the precautionary principle as embodying the Article 21 right to a clean environment in A.P. Pollution Control Board v. M.V. Nayudu (1999) 2 SCC 718. The cases collectively confirm that the international environmental principles, although not by themselves binding on Indian courts in the absence of an enabling statute, are part of the customary international law that, on the doctrine of incorporation accepted in Gramophone Co. of India v. Birendra Bahadur Pandey (1984) 2 SCC 534, becomes part of Indian law in the absence of express conflict with municipal law.

Conclusion

International environmental law has travelled a substantial distance from the Trail Smelter arbitration of 1938-41 to the Paris Agreement of 2015. Its conceptual core remains the no-harm rule that grew out of customary international law and the constellation of cooperative principles that successive conferences at Stockholm, Rio and Paris have generated. For Indian practice, the field is now indistinguishable from constitutional law: Articles 14, 21, 47, 48-A and 51-A(g) of the Constitution, read with the customary-international-law principles of sustainable development, precaution, polluter-pays and common but differentiated responsibilities, supply the constitutional charter for environmental protection in India. The deeper engagement is in the cross-referenced chapters on State jurisdiction, on the law of the sea and on landmark ICJ decisions.

Frequently asked questions

What is the difference between the Stockholm Declaration and the Rio Declaration?

The Stockholm Declaration of 1972 contains twenty-six principles that established the framework of international environmental law. The Rio Declaration of 1992 contains twenty-seven principles that built on Stockholm, integrating the concept of sustainable development articulated by the 1987 Brundtland Report and adding the precautionary principle (Principle 15), the polluter-pays principle (Principle 16) and common but differentiated responsibilities (Principle 7). Both Declarations are non-binding in form but their core principles have crystallised into customary international law and have been treated as binding by the International Court and by the Indian Supreme Court.

Are the precautionary principle and the polluter-pays principle part of Indian law?

Yes. The Indian Supreme Court in Vellore Citizens Welfare Forum v. Union of India (1996) 5 SCC 647 held that both principles had become part of customary international law and, since rules of customary international law that are not contrary to municipal law are deemed to have been incorporated in domestic law, both principles were part of Indian environmental law. The Court directed the closure of polluting tanneries discharging untreated effluent in Tamil Nadu. The principles have been reaffirmed in subsequent cases including the Bichhri case, the Taj Trapezium case, and A.P. Pollution Control Board v. M.V. Nayudu (1999) 2 SCC 718.

How is the Paris Agreement different from the Kyoto Protocol?

The Kyoto Protocol of 1997 set quantified, top-down emission-reduction commitments only for the developed-country Annex I Parties for two commitment periods (2008-2012 and 2013-2020). The Paris Agreement of 2015 abandons the top-down approach in favour of nationally determined contributions (NDCs) that every Party — developed or developing — communicates, maintains and progressively enhances. The Paris Agreement has a long-term temperature goal of holding the global average temperature increase to well below 2 degrees Celsius above pre-industrial levels and pursuing efforts to limit the increase to 1.5 degrees Celsius. The principle of common but differentiated responsibilities is preserved but reformulated as common but differentiated responsibilities and respective capabilities, in the light of different national circumstances.

What is sustainable development and how did it become part of Indian law?

Sustainable development was defined by the 1987 Brundtland Report as development that meets the needs of the present without compromising the ability of future generations to meet their own needs. It entered the Rio Declaration as Principle 4 and the Indian legal system through Vellore Citizens Welfare Forum v. Union of India (1996) 5 SCC 647, where the Supreme Court accepted that sustainable development as a balancing concept between ecology and development had been accepted as part of customary international law and was therefore part of Indian environmental law. The concept has since been applied in the Taj Trapezium case, the Goa Foundation mining cases and the T.N. Godavarman line of forest-conservation cases.

What is the constitutional basis for environmental protection in India?

The 42nd Amendment, 1976 inserted Article 48-A into the Directive Principles (the State shall endeavour to protect and improve the environment) and Article 51-A(g) into the Fundamental Duties (every citizen shall protect and improve the natural environment). The Indian Supreme Court has read the right to a clean environment into the Article 21 protection of the right to life beginning with Subhash Kumar v. State of Bihar (1991) 1 SCC 598. The Environment (Protection) Act, 1986 was enacted under Article 253 of the Constitution to give effect to the decisions taken at the Stockholm Conference of 1972 and supplies the umbrella statutory framework. The Water Act 1974, the Air Act 1981 and the National Green Tribunal Act 2010 supply the sector-specific framework.

Did the International Court of Justice recognise environmental protection as part of customary international law?

Yes. In its Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons (1996) ICJ Reports 226, the International Court declared that the 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 was now part of the corpus of international law relating to the environment. In Gabcikovo-Nagymaros (Hungary v. Slovakia) (1997) ICJ Reports 7, the Court adverted to the concept of sustainable development as a part of evolving environmental norms that had to be taken into consideration. In Pulp Mills (Argentina v. Uruguay) (2010) ICJ Reports 14, the Court confirmed the obligation of environmental impact assessment as part of general international law.