The Teesta water-sharing treaty between India and Bangladesh remains unsigned despite a near-final agreement in 2011, when West Bengal Chief Minister Mamata Banerjee withdrew consent at the last moment. As 2026 approaches, Bangladesh continues to press for a fair flow allocation during lean season months. The deadlock exposes a structural tension in Indian federalism: river-water treaties with foreign nations require Centre-state coordination, yet states hold effective veto power over riparian diplomacy.

The Teesta originates in the Sikkim Himalayas, flows through West Bengal, and enters Bangladesh before joining the Brahmaputra (called Jamuna in Bangladesh). It is a lifeline for Bangladesh's northern districts during the dry season (November–May), when flow drops sharply and irrigation demand peaks.

The 2011 draft agreement proposed a 42.5%–37.5% split in India's and Bangladesh's favour respectively, with the remaining share reserved for ecological flow. West Bengal's objection — that its own farmers would be left water-scarce — blocked the Centre from signing, illustrating how India's federal structure intersects with treaty-making under Article 253 of the Constitution. While Parliament can legislate on international agreements overriding state lists, conventions of cooperative federalism make unilateral Centre action politically untenable.

The Teesta dispute also has a China dimension: Beijing has offered to help Bangladesh build a Teesta river management project, introducing geopolitical stakes into a bilateral water row. For UPSC, the key static anchors are the river's basin geography, its tributaries (Rangit, Lachen, Lachung), the 2011 draft terms, and the comparative lens with the Ganga Water Treaty (1996) — the only successfully concluded India-Bangladesh river treaty — which allocated 35,000 cusecs to India and the remainder to Bangladesh at Farakka during lean season.