This article is written by Smaranika Sen from Kolkata Police Law Institute. This article exhaustively deals with the principles of International Environmental Law.


International Environmental Law comprises various multilateral or bilateral agreements, Conventions, etc. The main concern of such international law is to protect the environment and thereby create certain legislation in view of it.  In the mid-twentieth century, the onset of International Environmental Law was observed. Before this, there were only local movements or protests in order to protect the environment but there was no legislation. 

The source of International Environmental Law cannot be particularly mentioned in a kind. However, it can be stated that International Environmental Law has derived its roots from public international law. 

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Through this article, I will be discussing the fundamental principles of International Environmental Law.

Sources of International Environmental Law

The sources of International Environmental Law cannot be mentioned in a definite manner. However, after analysing its way of making laws, development, etc; few sources can be carved out. They are:

  • Treaties
  • Agreements
  • Customs

It has also been observed that developing international law is less traditional i.e. the laws made are based on present-day circumstances and are constantly changing with time, thus, it is not based solely on customs or traditions, and have more binding source; it is said so because the importance of environmental law is recognised worldwide and many countries have also made legislation regarding it. 

Principles of International Environmental Law

Sovereignty and responsibility

The above-mentioned principle is quite contradictory to each other in apparent vision. It is so because the principle of sovereignty tells that every state has sovereign rights over its natural resources. On the other hand, the principle of responsibility tells that no damage should be made to the environment by the state. It is now clearly evident that one principle tells that one has sovereign power and another principle states certain rules the sovereign power has to maintain. 

Now the question which arises is whether such contradicting principles can be implemented or not.

In the 1992 Rio Declaration, it was stated that:

“States have, in accordance with the Charter of the United Nations and the principles of the international law, the sovereign right to exploit their own resources pursuant to their own environmental and development 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.”

This shows that sovereign power is not absolute. It is subjected to certain restrictions. Therefore, here in this principle though the state enjoys a sovereign power over its natural resources its responsibility to not cause any damage to the environment is mandatory and not contradictory. 

Over time, the duty to not cause any damage to the environment has been accepted worldwide and it has also been backed by international treaties and laws. 

Now there are certain areas that are not under any jurisdiction of states like the high sea, In such cases what should one do? It is stated that here the principle of sovereignty may not apply but the principle of responsibility should always prevail. States should protect and conserve such environmental areas as common heritage.

Principle of good neighborliness and international cooperation

The principle of good neighborliness denotes the duty of states in view of not damaging the environment. The principle of international cooperation means that there should be an obligation where one cannot perform any such activities which are contrary to other states’ rights or which might harm their environment. This principle of international cooperation is believed to be based on this legal maxim sic utere tuo et alienum non laedas; meaning one should use their property in such a manner that they do not cause any harm to another. 

Besides avoiding any environmental damage, the principle of good neighborliness also states the duty of cooperation in identifying, investigating any damages. One might think that there already lies legislation among states regarding cooperation in the field of science, technology, socioeconomic, etc, then why does an international environmental law put emphasis on cooperation. This is so because the legislation regarding cooperation is not absolute. They are mostly limited to the cooperation regarding patents. 

Some other benefits of the principle of good neighborliness and international cooperation are the functions of prior notification and consultation. Due to prior notification and consultation, other states might provide some vital information about the environment. For example in times of natural calamities and emergencies. Other states on request can also provide consultation in times of need. 

Principle of preventive action 

Under this principle, the states remain under the obligation of not causing any damage to the environment within their own territory. However, this principle should be differentiated from the duty to avoid environmental harm. This principle mainly states that there should be some preventive action in the state regarding reducing wastes, reducing liability, and increasing efficiency. Discharge of toxic substances which exceed the reasonable limit should be stopped, it should rather be stopped at an early stage so that irreversible damage to the environment is not inflicted upon. There are certain ways in which the states have tried to implement preventive action. The ways are:

  • Use of penalties
  • Authorities established to particularly look into these preventive actions
  • Establishing environmental standards

It is believed that these ways are the golden ways in which irreversible damage can be stopped. This principle is recognised by various international instruments, treaties, etc. This principle is also reflected in the fifteen Rio Declaration.          

Where there are warnings 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.”It was the basis of the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal, 1989.      

Precautionary principle

This principle was first codified in the fifteen Rio Declaration. It was stated 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.”

Another Convention on Biological Diversity stated that “ where there is a threat of significant reduction or loss of biological diversity, lack of full scientific uncertainty should not be used as a reason for postponing measures to avoid or minimize such a threat.” This principle was mainly carved out because there are certain elements present in our environment which can cause certain extreme damages. However, at times waiting for scientific clarity and proper judgment regarding the burden of proof, the damage on the other hand can become irreversible. 

Now the question may arise why do the states need to wait for any scientific clarity when damage is already visible or is known. The answer is that whenever any states adopt any protective measures, the state has to prove beyond doubt that a specific substance or substances have caused damage, therefore states have to wait. But because of the precautionary principle, now states do not have to wait for proof of harm before taking any action. The first treaty to embody this principle was the 1985 Vienna Convention for the Protection of the Ozone Layer. Subsequently, it was widely addressed in various other instruments. However, it should be noted that the precautionary principle is always changing based on its circumstances, therefore, there is no precise formulae in its regard.

Principle of common but differentiated responsibility

The meaning of common but differentiated responsibility is that the common aim of all states should be protecting the environment, but having said that, certain states owing to their different ecological systems, physical appearances, geographical features might have to take more responsibility than other states. The basic idea of this principle is that all states should follow and obey international laws on the basis of equity and in accordance with their common but differentiated responsibilities and respective capacities. Two major principles of this principle are:

Common responsibility

It signifies that all the states must aim to conserve the environment together. They should not disregard their responsibility at any cost. They should not take advantage of their fellow states and not perform their own duty,

Differentiated responsibility 

States comprised of heavy industries, factories have to bear more precautionary measures or perform actions compared to a state which is filled with flaura and fauna. But each state has to keep in mind that while performing their differentiated responsibility, they cannot perform or form any such policies which are harmful or derogatory to their own state or other states.

The principle of sustainable development

The 1987 Brundtland Report first discussed the principle of sustainable development. It stated that the principle of sustainable development means a kind of development where the essential needs of especially the poor are met in the present without compromising the future generation’s ability to meet their needs. The primary focus of sustainable development in this regard is environmental protection. This principle has been accepted regionally as well as globally. There are three elements of sustainable development. The three elements are:

  • Integrational Equity- This means that each person must leave some kind of wealth (in this regard natural resources) for future generations, not less than what they have enjoyed in their lifetime so that the future generation can enjoy natural resources.
  • Sustainable use of natural resources- This aims at judicious, wise, careful, or rational use of natural resources.
  • Integration of environment and development- It is believed that without the integration of environment and development, the aim of sustainable development cannot be achieved. Thus, while making any environmental obligations, ecological and sociological development should also be taken into consideration. For example, in microeconomics, sustainable development would require the cost of environmental damage on the state which caused the damage. 

In the case of MC Mehta v Union of India and others (2001), the Supreme Court was analysing the case of vehicle pollution and it was held that non-CNG vehicles would be stopped and the country should enhance the use of CNG vehicles. In this case, the Supreme Court also stated that the principle of sustainable development is an important feature of environmental law.

The principle of absolute liability

The principle of absolute liability is implemented in a legal aspect in environmental law. It is applied in the environmental law to assess the risks of environmental law, and thereby the liability can be given to the person for unlawful acts. In a lot of states, the procedure of lawsuits regarding environmental cases or how one should file cases are not properly stated. In such cases compensation for the damage is hard to get. However, the application of absolute responsibility in the environmental law system makes it easier to get compensation. 

Polluter Pays principle

The basic meaning of this principle is that those who commence the act of pollution shall bear the cost of its management and prevention so that it does not harm the environment and human beings. The 1992 Rio Declaration has recognised the polluter pays principle. The primary arena of this principle is land, air, and water. We all know how much greenhouse gases have affected our environment. This principle can be applied to greenhouse gases. The principle can be implemented through a carbon price. The carbon price is a small charge which is paid by greenhouse gas emitters equivalent to the corresponding potential cost caused through future climate change, thus forcing emitters to internalize the cost of pollution. The carbon price can be paid in two ways:

  • In form of the carbon tax (direct method).
  • In the form of quota, here a certain limit is set and beyond it, the price has to be paid.

In the landmark case of MC Mehta v Kamal Nath (1996), the Court established the polluter pays principle in India. It was observed that the Motel Company encroached upon 27.12 bighas of land which also included forest land. This encroachment caused huge problems as there was constant movement of bulldozers and earthmovers to turn the course of the river for almost 5 months. This caused floods in the river and property worth 105 crores was destroyed. The Court held that the Motel Company should pay compensation for the destruction of the environment, thereby establishing the polluter pays principle.


Before discussing the principle of ecocentrism, let us understand what is the traditional concept of human beings towards the environment. Traditionally and even from a religious point of view, it has been observed that some people or groups of people believe that they are in dominion over the environment. Therefore, they can do whatever they like towards it. However, ecocentrism denotes a nature-centered concept. Here, it is stated that the human species are the consumers of almost everything in nature. They have the responsibility of conserving nature irrespective of the fact that they are getting any benefit from it or not. The ill-treatment of humans towards the environment is very dangerous as they are capable of harming the environment in such a way that the damage becomes irreversible. Thus, humans should take care, protect and conserve the environment.


The above-mentioned are some of the principles of environmental law. It is to be noted that international environmental law is still developing. Therefore, the interpretations of these principles remain open. There is no such precise boundary given to these principles. 


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