Bangladesh’s accession to the United Nations Water Convention is emerging as a significant turning point for transboundary water governance in South Asia. The move, supported by the UN as part of its global push for sustainable and cooperative water management, may recalibrate the balance of hydro-diplomacy in a region historically dominated by bilateral treaties and political sensitivities.

The U.N. Water Convention, formally known as the Convention on the Protection and Use of Transboundary Watercourses and International Lakes, is designed to promote cooperation and equitable sharing of shared water resources. For Bangladesh, one of the most water-stressed nations in the world, the decision to join represents both a strategic and ecological necessity. The country’s geography makes it acutely vulnerable to changing water flows, with 90% of its surface water originating beyond its borders, primarily from India and China.

Floods, droughts, and salinity intrusion in coastal zones have become more frequent due to climate change, glacier melt, and upstream interventions. Around two-thirds of Bangladesh’s population remains exposed to these climate-related water risks. The UN’s backing provides the country with a rules-based framework to negotiate its transboundary water rights more assertively, while also aligning with international standards of sustainable water management.

However, Bangladesh’s membership could also disrupt long-standing patterns of water diplomacy in the subcontinent. India, which shares 54 rivers with Bangladesh, has historically preferred bilateral water-sharing arrangements rather than multilateral oversight. The most notable example is the 1996 Ganges Water Sharing Treaty, which is set for renewal in 2026. The agreement governs how water from the Ganges is divided between the two nations during the dry season, but it has often been a source of contention.

Bangladesh’s new legal positioning under the UN Water Convention adds a multilateral dimension that India has so far avoided. By aligning itself with international norms, Bangladesh could gain stronger leverage in negotiations on water allocation and environmental safeguards. It also brings the possibility of third-party mediation or arbitration under UN auspices—something that India has traditionally resisted in regional matters.

The ripple effects of Bangladesh’s accession extend beyond the India-Bangladesh dynamic. The development introduces a potential new model for water governance that could appeal to other Himalayan basin nations such as Nepal and Bhutan. These countries also rely heavily on shared river systems and face growing pressures from hydropower expansion, deforestation, and climate variability. Should they follow Bangladesh’s lead, South Asia’s transboundary river politics could evolve from fragmented bilateralism toward a more coordinated, basin-wide approach.

China’s large-scale dam construction in Tibet further complicates the regional scenario. The new Motuo Hydropower Station, projected to be the world’s largest, has raised environmental and geopolitical concerns downstream. With the Brahmaputra River flowing from China through India into Bangladesh, upstream interventions have direct consequences for water availability, agriculture, and ecosystem health in both lower riparian countries.

In this context, the UN’s engagement could promote transparency and cooperation in managing shared waters. The Convention’s framework encourages data sharing, joint monitoring, and mechanisms to prevent water-related conflicts. For a region where river disputes have often intersected with political tensions, this marks a significant departure from ad hoc negotiations and opaque bilateral deals.

At the same time, India faces strategic dilemmas. Renewing the Ganges Treaty under heightened international scrutiny could invite demands for greater fairness and environmental accountability. Bangladesh’s proposal to create a new institutional mechanism for managing 14 shared rivers has already raised concerns in New Delhi about losing its dominant negotiating position.

Yet, proponents of regional cooperation argue that embracing multilateral water governance could yield long-term benefits for all. Collective management of transboundary waters can enhance resilience against floods and droughts, improve data transparency, and foster trust among neighboring nations. The UN’s backing lends legitimacy and global oversight to these goals, signaling that water diplomacy in South Asia can no longer remain confined to closed-door bilateralism.

Bangladesh’s entry into the UN Water Convention thus marks more than a diplomatic milestone—it reflects an emerging paradigm shift in the region’s approach to water security. If managed wisely, it could pave the way for a cooperative, sustainable framework for river governance across South Asia, transforming shared waters from sources of contention into channels of collaboration.