ANSWER | State Practice is fundamental to the formation of a custom but what amounts to a state practice and what constitute a States practice may cover every activities of the States organ or officials in an international context. It may includes Treaties, diplomatic correspondence and relations, opinion of national legal advisors, national legislation, policy statements , press releases, official manuals on legal questions, executive decisions and practices, decisions of international and national courts and practices of the international organisations.
Mutual relations among States:
Practice of states with other nations through its interactions constitutes evidences of practice of states followed in the sphere of international relations. Uniform practice among nations on a particular aspect leads to the formation of a customary rule. Rules also be evolved as a result of positive statements, interaction of the rival claims, acquiescence or intolerance of claims. The development of law of seas is an example for interaction of rival claims, compromise and mutual tolerance.
Right of passage over Indian Territory (India v. Portugal): Portugal claimed its right of passage on the Treaty of 1779 concluded between Portugal and Maratha Rulers. This right of passage granted in favour of Portugal was subsequently allowed by the British government as the sovereign of that part of the country which was with the Marathas. This right was confined to private persons, ciivil officials and goods in general to the extend necessary to exercise sovereignty by Portugal over these enclaves, but armed forces did not enjoy these rights. For the special permission was sought and granted by the British authorities. After independence, India also allowed this right.
The court ruled that India didn’t act contrary to its international obligations and the rights were suspended during 1954 because of the repercussion created by the events and tensions in Dadra in border territory of India. The Court also decided that Portugal was not entitled to send its armed forces through the Indian territory.
In the case of NorthSea Continental Shelf Case, the ICJ held that the passage of only a short period of time, it is not necessarily, a bar to the formation of a new rule of customary international law. It is indispensable requirement would be that within the period in question, short though it might be state practice including that of states whose interest are specially affected should have been both extensive and virtually uniform and should have occurred in such a way as to show a general recognition that a rule of law or legal obligation is involved.