Indian Council of World Affairs

Abstract: The 1996 Ganga Waters Treaty between India and Bangladesh is set to expire in December 2026. Any renewal of the treaty will be shaped by three converging factors: climate change has fundamentally altered the hydrological assumption on which the treaty was based; political alignment between West Bengal and the union government has removed a longstanding domestic obstacle to water diplomacy; and the recent political transition in Bangladesh has opened fresh diplomatic space for negotiation. Rather than treating the 2026 expiry as a procedural deadline, India and Bangladesh should seize it as an opportunity to negotiate a treaty framework capable of adapting to evolving climate realities and future hydrological uncertainties.   

Introduction 

In December 1996, the Ganga Water Treaty, a thirty-year agreement, was signed between India and Bangladesh for sharing the Ganga River water at the Farakka Barrage.^[i] The treaty was built on hydrological data and observed river flows between the 1949 and 1988 periods.^[ii] Since the river's hydrology has undergone structural changes that cannot be adequately captured by an  allocation schedule based on mid-twentieth-century data, the treaty was designed for a river system whose hydrological characteristics have since been transformed by  climate change.^[iii] As climate change reshapes rainfall patterns and increases the frequency of droughts, pressure on agriculture and water resources is expected to grow. During the dry season, when irrigation demand peaks, water availability is likely to become increasingly constrained. These changes introduce challenges that transcend conventional political considerations, making climate resilience an increasingly important dimension of the treaty’s future framework.

The monsoon patterns that supply most of the Ganga basin's annual water are changing; the key question is whether the 1996 treaty is still equipped to accommodate these shifts. Rainfall records compiled by the India Meteorological Department show that the monsoon is increasingly characterised by shorter but more intense rainfall events separated by longer dry spells.^[iv] Although total annual precipitation across much of the Ganga basin has remained relatively stable, changes in the temporal distribution of rainfall are creating significant challenges for both agriculture and river management.^[v]

These changes have direct implications for the Ganga Water Treaty because it governs only dry-season flows at Farakka,^[vi] when river discharge depends heavily on groundwater recharge during the preceding monsoon. As climate change concentrates rainfall into shorter, more intense events while lengthening dry spells, groundwater recharge and dry-season baseflows come under increasing pressure.^[vii] These climatic pressures are further compounded by expanding irrigation withdrawals in upstream states, particularly Uttar Pradesh and Bihar, where agricultural water demand has grown substantially since the treaty was signed in 1996.^[viii] Ninety per cent of India's freshwater withdrawals are by the agricultural sector, and the Ganga Basin is among the country's most heavily irrigated and agriculturally productive regions.^[ix] As a result, a significant share of the river's dry-season flow is already diverted before it reaches Farakka, leaving less water available for allocation under the treaty.^[x] Climate change alone did not produce this decline; increased human withdrawal has compounded the problem. Climate change is, however, likely to accelerate this trend at a pace that outstrips the diplomatic calendar of the 30-year treaty.

Renewing the treaty in its existing form would provide continuity and predictability of the treaty, but it would also retain a framework based on hydrological assumptions that are increasingly being challenged by climate change. A renewed agreement incorporating greater flexibility could therefore strengthen its long-term effectiveness for both countries.

Understanding the political significance of the 2026 treaty renegotiation requires considering the backdrop of environmental change. Political dynamics have undoubtedly shaped the context of the future treaty negotiations. Also relevant are the treaty's structural limitations, the domestic considerations facing Bangladesh's newly elected Prime Minister, Tarique Rahman, the political interests at play in West Bengal and the opportunities arising from alignment between the centre and the state. However, these considerations alone do not fully explain why the 2026 renegotiation assumes particular significance.

Political Alignment

For the first time in years, the political context surrounding the prospective treaty negotiations appears more conducive to engagement. The government in West Bengal is now politically aligned with the central government in New Delhi, removing a long-standing source of friction that has complicated previous bilateral discussions on water sharing. Simultaneously, the Rahman administration in Dhaka has signalled a cautious but constructive willingness to re-engage with India on transboundary issues.^[xi] This convergence of interest is rare, and it remains important. The December 2026 deadline, therefore adds a sense of urgency that both governments can use to sustain momentum towards substantial negotiations. 

And yet, despite this favourable political environment, there has been limited visible progress towards preparing for the treaty's renewal. While both governments have expressed willingness to engage, no formal joint working group, technical commission, or structured negotiation mechanism has yet been publicly established.^[xii] This is a challenge common to both India and Bangladesh: with the treaty deadline now only months away, the absence of a formal renegotiation architecture risks turning a rare political opening to dissipate into renewed bilateral friction. Political alignment creates favourable conditions, but such conditions require sustained institutional follow-through to translate into lasting outcomes. Without a successor framework in place by December, the two countries risk defaulting to an extension of a treaty whose terms have not kept pace with changing conditions on the ground. 

What is needed is not a revival of the 1996 treaty with cosmetic changes but a fundamentally redesigned agreement that reflects the river’s present reality and future uncertainty. The Ganga is no longer the river that the 1973 baseline data captured. A successor treaty must replace those static baselines with a real-time joint monitoring system that tracks what the river is actually doing, with clear trigger points at which allocations are automatically reviewed.^[xiii] It must contain a binding climate-adaptation clause that acknowledges the evolving nature of the Himalayan watershed and builds structured flexibility into the agreement itself. It must establish minimum ecological flows for the Hooghly,^[xiv] address the Farakka sedimentation problem that burdens Indian infrastructure and reduces downstream Bangladesh of sediment and flow,^[xv] and create a dispute resolution mechanism with genuine authority – not another consultative committee, but an institution empowered to act.^[xvi] These are not additions intended to project modernity; they constitute the baseline requirements for an agreement to remain viable for both countries under evolving climatic conditions.  

Conclusion 

As the 1996 Ganga Water Treaty approaches the end of its 30-year term, India and Bangladesh face an opportunity to move beyond a framework designed for a river system whose hydrology has fundamentally changed. The treaty has played an important role in sustaining bilateral cooperation, yet the growing influence of climate change, coupled with increasing upstream water demand and changing patterns of monsoon rainfall, has exposed the limitations of a static allocation mechanism. Renegotiation should focus not merely on revising water-sharing quotas but on developing a more adaptive framework capable of responding to evolving hydrological conditions.^[xvii] Incorporating provisions for periodic scientific review, real-time hydrological data sharing, and flexible flow management would enable both countries to respond more effectively to climatic variability while preserving the treaty's central objective of equitable and predictable water sharing.^[xviii] Rather than viewing the treaty's expiry as a source of uncertainty, India and Bangladesh should approach the renegotiation as an opportunity to strengthen one of South Asia's most enduring water-sharing arrangements and ensure that it remains resilient in an era of climate change.

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*Anushka Rupen, Research Intern, Indian Council of World Affairs, New Delhi
Disclaimer: Views expressed are personal. 

Endnotes 

^[i]  Treaty Between the Government of the Republic of India and the Government of the People's Republic of Bangladesh on Sharing of the Ganga/Ganges Waters at Farakka (New Delhi, December 12, 1996).  https://mowr.nic.in/core/WebsiteUpload/2023/2023011877.pdf.

^[ii] Kazi Saidur Rahman, Zahidul Islam, Umme Kulsum Navera, and Fulco Ludwig, “A Critical Review of the Ganges Water Sharing Arrangement,” Water Policy 21, no. 2 (2019): 259–276, https://doi.org/10.2166/wp.2019.164.

^[iii] Kazi Saidur Rahman, Zahidul Islam, Umme Kulsum Navera, and Fulco Ludwig, “A Critical Review of the Ganges Water Sharing Arrangement,” Water Policy 21, no. 2 (2019): 259–276. https://doi.org/10.2166/wp.2019.164.

^[iv] Ministry of Earth Sciences, Government of India, Assessment of Climate Change over the Indian Region (Singapore: Springer Nature, 2020), chap. 3, https://doi.org/10.1007/978-981-15-4327-2_3 The assessment, based on India Meteorological Department observations, reports increasing monsoon rainfall variability, including a 27 percent rise in the frequency of dry spells during 1981–2011 relative to 1951–1980 and increasing heavy rainfall intensity.

See also Press Information Bureau, Government of India, “The Indian Monsoon: Nature's Pulse and Nation's Lifeline,” 2025, https://www.pib.gov.in/PressNoteDetails.aspx?id=154892&NoteId=154892&ModuleId=3.

^[v]Ministry of Earth Sciences, Government of India, Assessment of Climate Change over the Indian Region (Singapore: Springer Nature, 2020), chap. 3, https://doi.org/10.1007/978-981-15-4327-2_3. 

^[vi] Government of India and Government of Bangladesh, Ganga Waters Treaty (1996), art. II. https://mowr.nic.in/core/WebsiteUpload/2023/2023011877.pdf

^[vii] Ministry of Earth Sciences, Government of India, Assessment of Climate Change over the Indian Region (Singapore: Springer Nature, 2020), chap. 3, https://doi.org/10.1007/978-981-15-4327-2_3 .

Abhijit Mukherjee, Soumendra Nath Bhanja, and Yoshihide Wada, “Groundwater Depletion Causing Reduction of Baseflow Triggering Ganges River Summer Drying,” Scientific Reports 8 (2018): 12049, https://doi.org/10.1038/s41598-018-30246-7, documenting the growing pressure on groundwater systems and the resulting decline in dry-season baseflows in the Ganga Basin.

^[viii]“Ganga, GAP, and Lockdown: Potential Threats to the Biodiversity of the River,” Journal of Water and Climate Change 15, no. 11 (2024): 5482, https://iwaponline.com/jwcc/article/15/11/5482/105443 ,

Down To Earth, January 2025, https://www.downtoearth.org.in/water.

^[ix] World Bank, “Annual Freshwater Withdrawals, Agriculture (% of Total Freshwater Withdrawal),” World Development Indicators, sourced from FAO AQUASTAT, https://data.worldbank.org/indicator/ER.H2O.FWAG.ZS.

^[x] Kazi Saidur Rahman, Zahidul Islam, Umme Kulsum Navera, and Fulco Ludwig, “A Critical Review of the Ganges Water Sharing Arrangement,” Water Policy 21, no. 2 (2019): 259–276, https://doi.org/10.2166/wp.2019.164 

^[xi] “West Bengal Assembly Election Results 2026 Highlights: BJP Buries TMC in a Landslide with over 200-Seat Win,” Deccan Herald, May 4, 2026, https://www.deccanherald.com/elections/west-bengal/west-bengal-assembly-election-results-2026-live-updates-a-change-of-guard-in-offing-or-will-bengal-pick-mamata-again-bjp-tmc-congress-mamata-modi-amit-shah-sir-election-commission-vote-counting-may-4-exit-polls-results-3989513, reporting the formation of a BJP-led government in West Bengal. See also Ashok Swain, “Tarique Rahman's Test at the Edge of the Ganga,” National Herald, February 22, 2026, https://www.nationalheraldindia.com/amp/story/opinion/tarique-rahmans-test-at-the-edge-of-the-ganga-india-bangladesh-water-sharing-treaty, examining how political developments in India and Bangladesh may shape the 2026 Ganga Treaty negotiations.

^[xii]Ashok Swain, “Tarique Rahman's Test at the Edge of the Ganga,” National Herald, February 22, 2026, https://www.nationalheraldindia.com/amp/story/opinion/tarique-rahmans-test-at-the-edge-of-the-ganga-india-bangladesh-water-sharing-treaty, discussing the political context surrounding the 2026 Ganga Treaty renewal, including the willingness of both governments to engage while highlighting the absence of publicly visible institutional preparations and the narrowing window for substantive negotiations. 

^[xiii] Shafi Md Mostofa, “Why the India-Bangladesh Ganges Treaty Renewal Must Deliver Real Security,” *The Diplomat*, April 13, 2026. The article proposes key elements for a successor Ganga Water Treaty, including guaranteed minimum dry-season flows based on updated hydrological conditions, a jointly operated real-time monitoring system, mandatory advance notification of upstream infrastructure developments, and adaptive review clauses linked to hydrological data rather than fixed political timelines.

^[xiv] World Bank, Ganga River Basin Planning Assessment Report (Washington, DC: World Bank, 2018), chap. 7, “Environmental Flows,” https://documents1.worldbank.org/curated/en/835371556798679943/pdf/Ganga-River-Basin-Planning-Assessment-Report.pdf. The assessment identifies environmental flows as essential for maintaining ecological integrity, navigation, and river-basin resilience under changing climatic and water-use conditions.

^[xv] Animesh K. Gain and Carlo Giupponi, “Impact of the Farakka Dam on Thresholds of the Hydrologic Flow Regime in the Lower Ganges River Basin (Bangladesh),” Water 11, no. 12 (2019): 2443, https://doi.org/10.3390/w11122443  . The study demonstrates that the operation of the Farakka Barrage has significantly altered downstream flow regimes and contributed to hydrological changes affecting the lower Ganges. See also World Bank, Ganga River Basin Planning Assessment Report (Washington, DC: World Bank, 2018), discussing the need for integrated sediment management and adaptive river-basin planning. https://documents1.worldbank.org/curated/en/835371556798679943/pdf/Ganga-River-Basin-Planning-Assessment-Report.pdf

^[xvi] Sohini Bose, “Rahman in New Delhi: Cautious Engagement in India–Bangladesh Ties,” *ORF Expert Speak*, April 17, 2026. The commentary argues that while the Joint Rivers Commission serves as the principal institutional mechanism for bilateral water cooperation, its effectiveness in resolving disputes depends on the broader state of India–Bangladesh relations, leaving limited institutional capacity to manage disagreements during periods of diplomatic strain.

^[xvii] Shafi Md Mostofa, “Why the India–Bangladesh Ganges Treaty Renewal Must Deliver Real Security,” The Diplomat, April 13, 2026, https://thediplomat.com/2026/04/why-the-india-bangladesh-ganges-treaty-renewal-must-deliver-real-security/. The article argues that the successor treaty should move beyond fixed water-sharing quotas by incorporating adaptive management, real-time hydrological monitoring, and review mechanisms capable of responding to changing climatic and hydrological conditions.

^[xviii] Kazi Saidur Rahman, Zahidul Islam, Umme Kulsum Navera, and Fulco Ludwig, “A Critical Review of the Ganges Water Sharing Arrangement,” Water Policy 21, no. 2 (2019): 259–276, https://doi.org/10.2166/wp.2019.164, identifying the limitations of the treaty's static allocation framework and the absence of adaptive management provisions.