International law — Sources — Custom — Local custom — Whether possible for legally binding custom to be based on relations between two States alone — Whether necessary to look to general international custom or general principles of law recognized by civilized nations in support of existence of local custom — Whether in absence of binding local custom State may rely on general customary law or general principles of law — Circumstances in which particular practice prevails over general rule.

State succession — International conventions — Treaties concerning rights over territory — Treaties creating personal rights and obligations — Right of passage over foreign territory to reach enclaves — Portuguese enclaves of Dadra and Nagar — Aveli in India.

Treaties — Conclusion and operation of — Conditions of validity — Criteria those of period when treaty signed — Treaty of Poona, 1779, between Portugal and Maratha Ruler.

Treaties — Termination of — By operation of law — In general — Clausula rebus sic stantibus — Extinction of treaty rights and obligations owing to changed relations between one Party and successor State to other Party — Treaty of Poona, 1779, between Portugal and Maratha Ruler.

International Court of Justice — Judicial function — Statute, Article 38 (1) — Judicial determination of rights on basis of international law — Degree of precision required for such determination — Relevance of difficulties in exercise of right and fulfilment of corresponding obligation.

International Court of Justice — Contentious jurisdiction — Competence — Acceptance of compulsory jurisdiction subject to reservation ratione temporis — Moment when dispute arises — Nature and subject of dispute — Distinction between facts or situations the existence of which is presupposed by dispute and facts or situations which are real cause of dispute.

International Court of Justice — Contentious jurisdiction — Competence — Acceptance of compulsory jurisdiction subject to reservation of questions falling exclusively within domestic jurisdiction of accepting State — Scope of reservation.

Territory — Nature of territorial sovereignty — Rights in and over territory — Enclaves — Sovereign rights of State in which enclaves situated — Right of passage over territory of that State for purpose of access to enclaves — Right of access necessarily presupposed by existence of enclaves — Discretionary right of sovereign of surrounding territory to refuse right of passage for reasons of internal security — Consistency of requirement of prior authorization with existence of right of passage — Effect upon exercise of right of passage of new de facto Government in enclaves opposed to Government of State claiming sovereignty over enclaves — Portuguese enclaves of Dadra and Nagar — Aveli in India.