Arbitration — Jurisdiction — Admissibility — Costs — Assessment of evidence — Scientific evidence

Environment — Principles of customary international environmental law — Relevance to interpretation and application of treaty on use of river waters — Effect of hydro-electric plant on downstream use of river waters

Rivers — Legal regulation — Indus Waters Treaty, 1960 — Hydro-electric plant — Whether State constructing plant entitled to divert waters from one tributary of river to another — Whether such diversion necessary — Limits on right of diversion — Duty to preserve minimum flow for benefit of downstream use by other State

Treaties — Interpretation — Principles of interpretation — Object and purpose of treaty — Need to interpret provisions of the treaty in mutually reinforcing fashion — Relevance of contemporary customary international law to interpretation of 1960 treaty — Environmental law — Application — Duty to apply treaty in good faith