Treaties — Related instruments — Interpretation — Unilateral suspension and abandonment — Customary law — Articles 60 to 62 of the Vienna Convention on the Law of Treaties — Approximate application — Countermeasures — Response to an internationally wrongful act — Proportionality — Unilateral action — Assumption of unilateral control of a shared resource — Distinction between a wrongful act and prior conduct of a preparatory character — Obligation to mitigate damages — Termination — Necessity not grounds for termination — Impossibility of performance — Permanent disappearance or destruction of an object indispensable for execution — Fundamental change of circumstances — Requirement that change be unforeseen — Circumstances constituting an essential basis — Stability of treaty relations — Material breach of the Treaty — Mutual repudiation of the Treaty — Reciprocal non-compliance — Termination by mutual consent — Integrity of the rule pacta sunt servanda

State responsibility — State of necessity as a ground for precluding the wrongfulness — Article 33 of the Draft Articles on State Responsibility — Essential interest — Grave and imminent peril — Act having to constitute the only means of safeguarding the interest threatened — Party having contributed to the occurrence of the state of necessity

Environment — Rivers — Effects of the Project on the environment — Emergence of new norms of environmental law — Sustainable development — Equitable and reasonable share of the resources of an international watercourse — Environmental Impact Assessment — No peremptory norms of environmental law — Treaty-based obligation to apply evolving standards to protect nature

State succession — Dissolution of Czechoslovakia — Article 12 of the Vienna Convention on Succession of States in Respect of Treaties, 1978 — Customary law — No effect on treaties creating rights and obligations attaching to territory

Damages — Ex injuria jus non oritur — Objectives of the Treaty — Purpose and intention of parties in concluding treaty prevailing over literal interpretation — Obligations overtaken by events — Recognition of positions adopted by the Parties after conclusion of the Treaty — Good faith negotiations — Joint regime — Reparation for acts committed by both Parties — Intersecting wrongs — Settlement of accounts for the construction