Customary International Law refers to international obligations arising from established state practices, rather than from formal written treaties or agreements. It is one of the primary sources of international law and is binding on all states, regardless of whether they have signed a treaty, provided they have not persistently objected to the custom. Here’s a detailed explanation: 1. Definition: Customary international law consists of rules and norms that have developed over time from the consistent and general practice of states, followed by them out of a sense of legal obligation (known as opinio juris). 2. Essential Elements: State Practice (Usus): There must be widespread, uniform, and consistent conduct by states over time. This includes actions by governments, legislation, court decisions, and diplomatic communications. Opinio Juris: States must follow the practice because they believe it is legally obligatory, not just out of courtesy, habit, or political expediency. 3. Examples of Customary International Law: The prohibition of genocide, torture, and slavery Rules of diplomatic immunity The principle of non-refoulement (not returning refugees to a country where they face harm) The law of the sea (prior to the codification in treaties like UNCLOS) 4. Importance: Customary international law plays a key role where no specific treaty exists. It fills gaps in international relations and ensures that even non-signatory states are bound by certain universal standards. 5. Application in India: Indian courts have recognized the role of customary international law in various judgments. As long as it does not conflict with Indian domestic law, customary international law can be applied in Indian courts. 6. Limitations: Proving a custom and the existence of opinio juris can be challenging. A state that consistently objects to a particular custom may not be bound by it (this is called the "persistent objector" rule). Conclusion: Customary international law is formed from the consistent and general practice of states, carried out with a belief that such practice is legally required. It is a vital source of international law and helps uphold global norms and standards, even in the absence of written agreements.

Customary international law refers to international obligations arising from established international practices, as opposed to obligations arising from formal written conventions and treaties . Customary international law results from a general and consistent practice of states that they follow from a sense of legal obligation. Two examples of customary international laws are the doctrine of non-refoulement and the granting of immunity for visiting heads of state. International Jurisdiction The International Court of Justice (ICJ) is the main judicial body of the United Nations , and it settles disagreements between member states of the United Nations. Under Chapter II, Article 38 of the Statute of the International Court of Justice , international customs and general practices of nations shall be one of the court's sources of customary international law is one of the sources of international law . Customary international law can be established by showing (1) state practice and (2) opinio juris .

Customary international law is used to refer to international duties ensuing from accepted international practice, as opposed to duties ensuing from formal written conventions and treaties. Customary international law ensues from a general and persistent practice of states that they pursue out of a sense of legal obligation. The doctrine of non-refoulement and the extension of immunity for visiting heads of state are two examples of customary international laws. The International Court of Justice (ICJ) is the principal court of the United Nations, and it resolves disputes among United Nations member states. In accordance with Chapter II, Article 38 of the Statute of the International Court of Justice, international usages and general practices of states shall be one of the sources of customary international law is one of the sources of international law.