Teesta

The Teesta (Bengali: তিস্তা) is a major trans-boundary river of the eastern Himalayan system, rising from the Tso Lhamo and Khangchung Chho lakes in northern Sikkim, descending through Darjeeling and West Bengal in India, and entering Bangladesh near Mekhliganj before joining the Brahmaputra (Jamuna) at Chilmari. It drains roughly 12,540 square kilometres, of which about 2,800 square kilometres lie in Bangladesh, and is the lifeline of the country's northern Rangpur division, feeding the Teesta Barrage Irrigation Project at Dalia (Lalmonirhat). The river is governed in principle by the framework of the Indo-Bangladesh Joint Rivers Commission (JRC), constituted in 1972, which oversees the 54 rivers shared between the two states.

The core dispute concerns equitable dry-season (lean-period) flow. India's Gajoldoba Barrage in West Bengal diverts water upstream, sharply reducing flow into Bangladesh between December and March when both countries' irrigation demand peaks. An ad hoc sharing arrangement of 1983 allotted 39 per cent to India and 36 per cent to Bangladesh, leaving 25 per cent unallocated, but it lapsed without implementation. A comprehensive Teesta Water Sharing Agreement was finalised at the official level in 2011, slated for signing during Prime Minister Manmohan Singh's Dhaka visit, but was blocked at the eleventh hour by West Bengal Chief Minister Mamata Banerjee, who cited the state's own water needs — illustrating how India's federal structure and the constitutional status of water as a State subject (Entry 17, State List) constrain Union treaty-making. The deal has remained stalled ever since.

The Teesta has acquired sharp geopolitical salience. China has offered to finance a comprehensive Teesta River Comprehensive Management and Restoration Project, a roughly one-billion-dollar dredging, embankment and reservoir scheme on the Bangladesh stretch; India, wary of Chinese engineering near its strategically narrow Siliguri Corridor (the "Chicken's Neck"), signalled in 2024 its own willingness to fund and execute the project, turning the river into an arena of Sino-Indian competition. The political transition in Bangladesh following the fall of the Sheikh Hasina government in August 2024 has further clouded the project's status, which remains unsettled as of 2026. The Teesta also intersects the wider unresolved cluster of Indo-Bangladesh water issues alongside the Ganges (governed by the 1996 Ganga Water Treaty, expiring 2026) and the Feni.

For BCS aspirants, the Teesta is a recurring item in Bangladesh Affairs and Bangladesh and International Affairs. Examiners test the chronology (1972 JRC, 1983 ad hoc share, 2011 stalled accord), the institutional machinery (Joint Rivers Commission), the domestic Indian obstacle (Mamata Banerjee, federalism), the infrastructure (Teesta Barrage, Gajoldoba, Dalia), and increasingly the China-India strategic triangle around the Siliguri Corridor. Analytical questions ask candidates to weigh Bangladesh's lower-riparian claims under the principles of equitable and reasonable utilisation reflected in the 1997 UN Watercourses Convention, and to assess how the Teesta and Ganges treaties shape bilateral relations.