Sources of Environmental Law: The Constitution, Environmental Statutes, Delegated Legislation, Judicial Precedents, International Environmental Law and Customary International Environmental Law

Indian environmental law has no single code. Its rules are drawn from six formal sources: the Constitution, parliamentary and State statutes, delegated legislation, judicial precedents, treaties, and customary international law. Each source has its own authority, its own method of creation and its own limits. This topic examines each in turn and explains how they interact.

1. Meaning and Classification of Sources

Following Salmond, a formal source is that from which a rule derives its force and validity, while a material source is that from which it derives its content. The Environment (Protection) Act, 1986 is a formal source; the Stockholm Declaration, scientific evidence and India's traditional conservation ethic are material sources that shaped its content.

Source	Nature	Principal examples
Constitution	Formal; supreme	Articles 21, 48A, 51A(g), 252, 253; Seventh Schedule
Statutes	Formal; enacted by legislature	Water Act, 1974; Air Act, 1981; EPA, 1986; NGT Act, 2010
Delegated legislation	Formal; made by the executive under statutory authority	Environment (Protection) Rules, 1986; EIA Notification, 2006
Judicial precedents	Formal; binding under Article 141	Vellore, Kamal Nath, Oleum Gas
International environmental law	Formal once implemented or received; otherwise persuasive	Rio Declaration, CBD, Paris Agreement
Customary international law	Formal where received and not inconsistent with domestic law	Duty to prevent transboundary harm; sustainable development
Traditional, religious and ethical ideas	Material only	Prithvi Sukta; Bishnoi and Chipko traditions

✦ Mnemonic: 'C-S-D-J-I-C'

'Clever Students Don't Just Imitate, they Create': Constitution, Statutes, Delegated legislation, Judicial precedent, International law, Customary international law. The order also reflects the hierarchy most answers should follow.

2. The Constitution as a Source

The Constitution is the supreme source. It confers rights, imposes duties, distributes legislative power and provides remedies. It did not mention the environment in 1950; the Forty-second Amendment (1976) and judicial interpretation of Article 21 made it the foundation of the subject.

2.1 Environmental provisions of the Constitution

Part	Provision	Environmental significance
Fundamental Rights	Article 14	Arbitrary grant of clearances or natural resources struck down; source of the climate right (Ranjitsinh, 2024)
	Article 19(1)(g) and (6)	Trade subject to reasonable restrictions in the interest of the general public, including environmental restrictions
	Article 21	Right to a wholesome environment, clean water, freedom from noise, and freedom from the adverse effects of climate change
	Articles 25 and 26	Religious and cultural rights of communities in natural sites (Niyamgiri, 2013)
	Article 32	Right to move the Supreme Court; basis of environmental PIL
Directive Principles	Article 39(b)	Material resources to be distributed to subserve the common good
	Article 47	Improvement of public health
	Article 48A	State to protect and improve the environment and safeguard forests and wildlife
	Article 49	Protection of monuments and places of national importance
	Article 51(c)	Foster respect for international law and treaty obligations
Fundamental Duties	Article 51A(g)	Citizen's duty to protect and improve the natural environment
Local government	Articles 243G and 243W; Eleventh and Twelfth Schedules	Environmental functions of panchayats and municipalities
Legislative relations	Articles 246, 252 and 253; Seventh Schedule	Distribution of power; legislation by consent of States; legislation to implement treaties
Water disputes	Article 262	Adjudication of inter-State river water disputes
High Courts	Article 226	Writ jurisdiction in environmental matters

Article 252(1) — Power of Parliament to legislate for two or more States by consent (in brief)

If the Legislatures of two or more States pass resolutions that it is desirable that a matter on which Parliament has no power to legislate for the States (except under Articles 249 and 250) should be regulated by Parliament by law, Parliament may make such a law. It applies to those States and to any other State that later adopts it by resolution.

The Water (Prevention and Control of Pollution) Act, 1974 was enacted in this way, because water is a State subject (Entry 17, List II).

📖 State of Tamil Nadu v. Hind Stone, (1981) 2 SCC 205

Facts: Tamil Nadu refused to renew private leases for quarrying black granite and reserved the mineral for a State corporation. The lessees claimed a violation of Article 19(1)(g).

Held: Rivers, forests, minerals and similar resources constitute the nation's natural wealth. They are not to be frittered away and exhausted by any one generation; every generation owes a duty to all succeeding generations to develop and conserve them. The State's policy was upheld.

Ratio: Articles 39(b) and 19(6) together allow the State to regulate natural resources for conservation and intergenerational benefit.

⚠ Non-justiciable provisions still operate as sources

Article 48A (a Directive Principle) and Article 51A(g) (a Fundamental Duty) are not directly enforceable. Yet they are genuine sources of environmental law: courts use them to interpret Article 21, to judge the reasonableness of restrictions under Article 19, and to review executive action (Sachidanand Pandey v. State of West Bengal, 1987).

3. Environmental Statutes

3.1 Classification of environmental statutes

Category	Statutes	Character
Umbrella legislation	Environment (Protection) Act, 1986	General powers over all media; framework for rules
Media-specific	Water Act, 1974; Air Act, 1981	Pollution control boards and consent regime for one medium
Resource-specific	Indian Forest Act, 1927; Wild Life (Protection) Act, 1972; Van (Sanrakshan Evam Samvardhan) Adhiniyam, 1980; Biological Diversity Act, 2002	Conservation of natural resources
Rights of communities	Forest Rights Act, 2006	Recognition of forest rights and community role in conservation
Liability and compensation	Public Liability Insurance Act, 1991; Bhopal Gas Leak Disaster (Processing of Claims) Act, 1985	Relief to victims of hazardous accidents
Institutional and adjudicatory	NGT Act, 2010; Commission for Air Quality Management Act, 2021; Compensatory Afforestation Fund Act, 2016	Create bodies and funds
Cross-cutting laws with environmental provisions	Factories Act, 1948 (Chapter IVA on hazardous processes); Motor Vehicles Act, 1988; SHANTI Act, 2025 (nuclear energy); Insecticides Act, 1968; Energy Conservation Act, 2001; BNS and BNSS	Environmental rules within laws enacted for other purposes
State legislation	Tree preservation Acts; State groundwater Acts; Kerala Conservation of Paddy Land and Wetland Act, 2008	Local conservation measures

3.2 The EPA as umbrella legislation

The EPA was enacted after Bhopal to fill the gaps left by media-specific statutes. It confers on the Central Government a general power to take all measures to protect and improve the environment (Section 3), to issue directions including closure (Section 5), and to make rules on almost every aspect of environmental regulation (Section 6). Most of the operative law in India, from impact assessment to waste management, is found in rules and notifications made under these three sections.

Section 24, EPA — Effect of other laws

(1) Subject to the provisions of sub-section (2), the provisions of this Act and the rules or orders made therein shall have effect notwithstanding anything inconsistent therewith contained in any enactment other than this Act.

(2) Where any act or omission constitutes an offence punishable under this Act and also under any other Act then the offender found guilty of such offence shall be liable to be punished under the other Act and not under this Act.

3.3 Interpretation of environmental statutes

Environmental statutes are social welfare legislation and receive a purposive and liberal interpretation that advances their protective object. In T.N. Godavarman (1997) the word 'forest' was given its dictionary meaning so as to extend protection to all forests regardless of ownership or classification. Where a provision is ambiguous, courts prefer the reading that is consistent with Articles 21, 48A and 51A(g) and with the precautionary principle.

4. Delegated Environmental Legislation

Delegated legislation is law made by the executive or a subordinate authority under power conferred by a statute. It is the backbone of environmental law, because environmental regulation requires technical detail, frequent revision and speed that Parliament cannot supply.

4.1 Why delegation dominates

Technicality. Standards expressed in micrograms and decibels require scientific input.
Flexibility. Standards must change as science and technology change.
Speed. Emergencies, such as a chemical leak or an air quality crisis, need immediate measures.
Local variation. Different areas need different controls, as with eco-sensitive zone notifications.

4.2 Enabling provisions

Statute	Rule-making and notification powers
EPA, 1986	Section 3 (measures, including standards and restriction of areas), Section 5 (directions), Section 6 (rules to regulate environmental pollution), Section 25 (general rule-making power)
Water Act, 1974	Sections 63 and 64 (rules by the Central and State Governments)
Air Act, 1981	Sections 53 and 54 (rules by the Central and State Governments)
Wild Life (Protection) Act, 1972	Sections 63 and 64
Biological Diversity Act, 2002	Rules and regulations under the Act

4.3 Principal instruments of delegated environmental legislation

Instrument	Subject
Environment (Protection) Rules, 1986	Standards, restriction of industries in areas (Rule 5), environmental statement (Rule 14)
Manufacture, Storage and Import of Hazardous Chemical Rules, 1989	Safety in handling hazardous chemicals
Chemical Accidents (Emergency Planning, Preparedness and Response) Rules, 1996	Crisis groups and emergency planning
Noise Pollution (Regulation and Control) Rules, 2000	Ambient noise standards; loudspeakers
Ozone Depleting Substances (Regulation and Control) Rules, 2000	Implementation of the Montreal Protocol
EIA Notification, 2006	Prior environmental clearance and public hearing
Hazardous and Other Wastes, Plastic Waste, Bio-Medical Waste and Construction and Demolition Waste Rules, 2016	Waste streams, with extended producer responsibility for plastics
Wetlands (Conservation and Management) Rules, 2017	Protection of notified wetlands
CRZ Notification, 2019	Coastal regulation zones
E-Waste (Management) Rules, 2022; Battery Waste Management Rules, 2022	Electronic and battery waste; extended producer responsibility
Solid Waste Management Rules, 2026	Replaced the 2016 Rules from 1 April 2026; four-stream segregation (wet, dry, sanitary and special care waste) and duties of bulk waste generators

4.4 Controls on delegated environmental legislation

Control	How it operates
Parliamentary	Rules under the EPA must be laid before each House of Parliament, which may modify or annul them (Section 26, EPA)
Procedural	Draft notifications restricting industries in an area must ordinarily be published for public objections for sixty days (Rule 5(3), Environment (Protection) Rules), subject to a public interest exception (Rule 5(4))
Judicial	Delegated legislation may be struck down if it exceeds the parent Act, conflicts with a superior instrument, is manifestly arbitrary or violates fundamental rights

📖 Indian Council for Enviro-Legal Action v. Union of India (CRZ case), (1996) 5 SCC 281

Facts: Coastal States had failed to prepare coastal zone management plans, and the Central Government had relaxed some restrictions of the 1991 CRZ Notification.

Held: The Court struck down a relaxation that reduced the no-development zone along tidal rivers, holding that the power to amend the notification could not be used in a way contrary to the object of the EPA. States were directed to prepare management plans and enforce the notification.

Ratio: Delegated environmental legislation is subject to the protective purpose of the parent Act; it cannot be diluted arbitrarily.

The same principle underlies Alembic Pharmaceuticals v. Rohit Prajapati (2020), where an administrative circular permitting clearance after commencement was held contrary to the EIA Notification. In the Vanashakti litigation the Supreme Court in July 2026 applied the same idea: it upheld a time-bound 2017 notification made under Section 3 of the EPA but quashed a 2021 office memorandum that created a standing route to post-facto clearance, holding that such relaxation can be made only by statutory notification.

5. Judicial Precedents as a Source

In India, judicial decisions are not only a source of environmental law; they are its most dynamic source. Many of the subject's core principles exist because the Supreme Court declared them.

5.1 Constitutional basis

Provision	Effect
Article 141	Law declared by the Supreme Court is binding on all courts in India
Article 142	The Supreme Court may pass any order necessary for doing complete justice, which it has used to issue environmental guidelines and directions
Article 144	All authorities, civil and judicial, shall act in aid of the Supreme Court
Article 32 and 226	Writ jurisdiction through which environmental PIL is heard

5.2 Principles created or received by the courts

Principle	Case
Absolute liability	M.C. Mehta v. Union of India (Oleum Gas), (1987) 1 SCC 395
Polluter pays	Indian Council for Enviro-Legal Action v. Union of India, (1996) 3 SCC 212
Sustainable development; precautionary principle	Vellore Citizens' Welfare Forum v. Union of India, (1996) 5 SCC 647
Public trust doctrine	M.C. Mehta v. Kamal Nath, (1997) 1 SCC 388
Reverse burden of proof	A.P. Pollution Control Board v. M.V. Nayudu, (1999) 2 SCC 718
Ecocentrism	Centre for Environmental Law, WWF-India v. Union of India, (2013) 8 SCC 234
Environmental rule of law	Hanuman Laxman Aroskar v. Union of India, (2019) 15 SCC 401
Right against adverse effects of climate change	M.K. Ranjitsinh v. Union of India, 2024 INSC 280

5.3 Judicial techniques

Public interest litigation and epistolary jurisdiction. Letters and newspaper reports treated as writ petitions.
Continuing mandamus. Keeping a case open for years to supervise compliance, as in T.N. Godavarman and the Delhi air pollution cases.
Expert committees. The Central Empowered Committee, created by the Court in the Godavarman litigation in 2002, was given statutory status as a body under Section 3(3) of the EPA in 2023.
Amicus curiae and court commissioners to investigate and report.
Environmental compensation measured by the cost of restoration.

5.4 The National Green Tribunal

Decisions of the NGT bind the parties and are a major source of environmental law in practice. An appeal lies to the Supreme Court under Section 22 of the NGT Act.

📖 Municipal Corporation of Greater Mumbai v. Ankita Sinha (Supreme Court, 7 October 2021)

Facts: The question was whether the National Green Tribunal could take up environmental matters on its own motion, since the NGT Act speaks only of applications and appeals.

Held: The NGT is a unique forum with a wide mandate. Its role is not merely adjudicatory; it also performs preventive, remedial and ameliorative functions. It can take up matters suo motu, including on the basis of letters and media reports, provided the principles of natural justice are followed.

Ratio: The NGT's jurisdiction is to be read purposively so that it can effectively protect the environment.

⚠ Criticism of judge-made environmental law

The Supreme Court's role has been described as 'judicial governance'. Critics point to the lack of technical expertise in courts, the difficulty of supervising compliance, and the blurring of the separation of powers. Defenders reply that the courts acted only because the executive failed to enforce the law. A balanced answer notes both views.

6. International Environmental Law as a Source

International environmental law consists of the rules and principles that govern the conduct of States in relation to the environment. Its sources are those listed in Article 38(1) of the Statute of the International Court of Justice: treaties, international custom, general principles of law, and, as subsidiary means, judicial decisions and the teachings of the most highly qualified publicists. Declarations such as Stockholm and Rio are non-binding soft law, but they have shaped both treaties and custom.

6.1 How international law enters Indian law

Treaties require implementation. India follows a dualist approach to treaties. A treaty does not by itself create rights enforceable in Indian courts; Parliament must legislate, which it may do under Article 253 even on State subjects (Maganbhai Ishwarbhai Patel v. Union of India, (1970) 3 SCC 400).
Courts read domestic law consistently with treaties. Where domestic law is silent or ambiguous, courts may use international conventions to give content to fundamental rights, provided there is no inconsistency (Vishaka v. State of Rajasthan, (1997) 6 SCC 241).
Customary international law is incorporated. Rules of customary international law are part of Indian law unless they conflict with an Act of Parliament (Gramophone Company of India v. Birendra Bahadur Pandey, (1984) 2 SCC 534).

6.2 Major multilateral environmental agreements and their Indian implementation

Agreement	Subject	Indian implementation
Ramsar Convention, 1971	Wetlands of international importance	Wetlands Rules, 2017; designation of Ramsar sites
Stockholm Conference, 1972 (decisions)	Human environment	Air Act, 1981; EPA, 1986 (both under Article 253)
CITES, 1973	International trade in endangered species	Chapter VB of the Wild Life (Protection) Act, inserted in 2022
Vienna Convention, 1985 and Montreal Protocol, 1987	Ozone layer	Ozone Depleting Substances Rules, 2000
Basel Convention, 1989	Transboundary movement of hazardous wastes	Hazardous and Other Wastes Rules, 2016
UNFCCC, 1992; Kyoto Protocol, 1997; Paris Agreement, 2015	Climate change	National Action Plan on Climate Change; Energy Conservation (Amendment) Act, 2022 and carbon credit trading
Convention on Biological Diversity, 1992; Nagoya Protocol, 2010	Biodiversity; access and benefit sharing	Biological Diversity Act, 2002 (amended 2023)
UN Convention to Combat Desertification, 1994	Land degradation	National action programmes
Kunming-Montreal Global Biodiversity Framework, 2022	Biodiversity targets for 2030	National biodiversity strategy and action plan

6.3 Soft law instruments

Instrument	Significance
Stockholm Declaration, 1972	26 principles; Principle 1 (right to environment) and Principle 21 (sovereignty and responsibility not to cause transboundary harm)
World Charter for Nature, 1982	UN General Assembly statement that every form of life is unique and warrants respect
Rio Declaration, 1992	27 principles, including 3 and 4 (sustainable development), 10 (access rights), 15 (precaution) and 16 (polluter pays)
Agenda 21 (1992); Sustainable Development Goals (2015)	Programmes of action
UN General Assembly Resolution 76/300 (2022)	Right to a clean, healthy and sustainable environment

7. Customary International Environmental Law

Customary international law is 'evidence of a general practice accepted as law' (Article 38(1)(b), ICJ Statute). It has two elements: State practice (usus), which must be general and consistent, and opinio juris, the belief that the practice is legally required (North Sea Continental Shelf cases, ICJ, 1969). Custom binds all States, whether or not they are parties to any treaty, which makes it especially important in the environmental field.

7.1 Principles and their customary status

Principle	Authority	Status
No-harm principle: duty to prevent significant transboundary environmental harm	Trail Smelter arbitration (1938 and 1941); Corfu Channel (ICJ, 1949); Stockholm Principle 21; Rio Principle 2; Legality of the Threat or Use of Nuclear Weapons (ICJ Advisory Opinion, 1996)	Firmly established custom
Duty to carry out an environmental impact assessment for activities with a risk of significant transboundary harm	Pulp Mills on the River Uruguay (Argentina v. Uruguay), ICJ 2010; Certain Activities (Costa Rica v. Nicaragua), ICJ 2015	Established custom
Duty to co-operate, notify and consult	Lac Lanoux arbitration (1957); Pulp Mills	Established custom
Sustainable development	Gabčíkovo-Nagymaros (ICJ, 1997)	Recognised concept; status as a binding rule debated
Precautionary principle	Rio Principle 15; ITLOS Seabed Disputes Chamber Advisory Opinion (2011), noting a trend towards its becoming custom	Emerging; contested
Polluter pays principle	Rio Principle 16	Largely a policy principle in international law
Common but differentiated responsibilities	Rio Principle 7; UNFCCC; Paris Agreement	Treaty-based

📖 Trail Smelter Arbitration (United States v. Canada), 1938 and 1941

Facts: Sulphur dioxide fumes from a smelter at Trail in British Columbia, Canada damaged crops and forests in the State of Washington, United States.

Held: Under the principles of international law, 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, when the case is of serious consequence and the injury is established by clear and convincing evidence. Canada was held responsible and a regime of controls was imposed on the smelter.

Ratio: The foundational statement of the no-harm principle, later restated in Stockholm Principle 21.

Stockholm Declaration, 1972 — Principle 21

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.

📖 Pulp Mills on the River Uruguay (Argentina v. Uruguay), ICJ Reports 2010, p. 14

Facts: Uruguay authorised pulp mills on a river shared with Argentina, which complained of breaches of a bilateral statute and of risk of pollution.

Held: Uruguay had breached its procedural obligations to inform and negotiate. The Court recognised that it may now be considered a requirement under general international law to undertake an environmental impact assessment where there is a risk that a proposed industrial activity may have a significant adverse impact in a transboundary context. No breach of substantive obligations was proved.

Ratio: Environmental impact assessment is part of the customary duty of due diligence.

7.2 The ICJ Advisory Opinion on climate change (2025)

In its Advisory Opinion on the Obligations of States in respect of Climate Change (23 July 2025), the International Court of Justice confirmed that the customary duty to prevent significant harm to the environment and the duty to co-operate apply to the climate system, alongside the obligations in the climate treaties, and that States must act with stringent due diligence. It also recognised that a clean, healthy and sustainable environment is essential for the enjoyment of human rights.

7.3 Reception of customary international environmental law in India

📖 Vellore Citizens' Welfare Forum v. Union of India, (1996) 5 SCC 647

Held: Once the principles of sustainable development, including the precautionary principle and the polluter pays principle, are accepted as part of customary international law, there is no difficulty in accepting them as part of domestic law. Rules of customary international law which are not contrary to municipal law are deemed to be incorporated in the domestic law and are to be followed by the courts.

Ratio: The doctrine of incorporation applies to customary international environmental law. India received these principles through the courts, without legislation.

⚠ A point of critical analysis

In Vellore the Supreme Court treated the precautionary and polluter pays principles as customary international law, although their status in international law was, and remains, contested. The result in India is that these principles have firmer legal status domestically than they have internationally. Section 20 of the NGT Act has since placed them on a statutory footing, which removes any doubt in Indian law.

✦ Comparing the two international sources

Treaties bind only parties and, in India, need legislation (Article 253). Custom binds all States and, in India, is incorporated automatically unless it conflicts with a statute (Gramophone, Vellore). Remember: 'Treaties need a bridge; custom walks in.'

8. Interaction and Hierarchy of Sources

The Constitution is supreme. Statutes and delegated legislation inconsistent with it are void.
Statutes prevail over delegated legislation. Rules and notifications must stay within the parent Act.
Judicial precedents interpret and supplement. Under Article 141 they bind all courts, and under Article 142 they may fill gaps until the legislature acts.
International law is received subject to domestic law. Treaties need legislation; custom is incorporated only where it does not conflict with statute.
Material sources inform all of them. Science, ethics and tradition shape the content of each formal source.

9. Related Topics and Provisions

Topic or provision	Connection
Environmental law: introduction, meaning and scope	Overview of sources and the distribution of legislative power
Environmental law as public, regulatory and human rights law	Delegated legislation as the regulatory backbone; rights under Article 21
Environmental law and sustainable development	The principle received through customary international law
Articles 21, 48A, 51A(g), 141, 142, 252 and 253	Constitutional basis of the sources
Sections 3, 5, 6, 24, 25 and 26, EPA	Powers, rule-making, overriding effect and parliamentary control
Section 20, NGT Act	Statutory recognition of judge-made and international principles
Article 38(1), ICJ Statute	Sources of international law