The Battle For Siang: Arunachal Pradesh's Mega Dam Dilemma

The Siang is a river that carries more than water through Arunachal Pradesh. For the Adi communities living along its banks, it carries memory, ancestry and a way of life shaped by the land. Now, a proposed dam of extraordinary scale threatens to turn that familiar landscape into the site of a national debate over electricity, security and development.

In October, opposition to the 11,200 MW Siang Upper Multipurpose Project (SUMP) escalated into clashes, arrests and restrictions on public gatherings, sharpening a question that has followed the project for years: who gets to decide the future of a river and the people who live beside it?

What Is The Siang Project, And Why Does The Centre Want It?

The Siang Upper Multipurpose Project is a proposed 11,200 MW hydropower and water-storage project on the Siang river in Arunachal Pradesh. The proposal evolved from plans for two separate projects into a single, larger multipurpose dam. The project is being developed by the National Hydroelectric Power Corporation (NHPC), but it has not reached the construction stage. Authorities are conducting pre-feasibility work to assess whether and where the project could be built. The government says this exercise is a technical assessment, not a final decision to proceed.

The project’s strategic importance is tied to China’s plans upstream. The Siang enters India from Tibet, where the river is known as the Yarlung Tsangpo, before flowing into Assam as the Brahmaputra. China approved a major hydropower project on the lower reaches of the Yarlung Tsangpo in December 2024. Indian officials and state leaders have argued that a large reservoir on the Indian side could help store and regulate water, particularly if upstream releases create sudden changes in downstream flows. The project is therefore being presented not simply as a source of electricity, but as a potential instrument of water security.

Yet the strategic argument has not settled the debate. Critics question whether the proposed dam can reliably protect downstream communities from risks originating upstream, and warn against treating a geopolitical concern as sufficient justification for a project with enormous local consequences. A reservoir’s capacity to regulate flows, they argue, must be weighed against the environmental, social and geological risks of building it in the eastern Himalayas.

Why Are Local Communities Opposed?

For many Adi residents, the fear is not confined to the loss of houses or farmland. The project is expected to affect ancestral settlements, agricultural land and the cultural landscape around the Siang. Community groups have warned that 27 villages could be submerged, with others affected indirectly. The precise extent of displacement and damage remains subject to detailed assessment, but the prospect alone has become a source of deep anxiety among people whose livelihoods and identity are rooted in the valley.

The Siang also has a spiritual and cultural significance that cannot be measured in megawatts. Adi organisations have invoked traditional institutions, including the kebang, a community council through which collective decisions are discussed. In August 2025, a rare gathering of the Bogum Bokang Kebang brought Adi groups together to oppose the dam and the pre-feasibility surveys. For these communities, the dispute is also about whether decisions over ancestral land can be made without their meaningful consent. Researchers studying the resistance say that the exclusion of indigenous communities from decision-making is central to the conflict.

Environmental and geological concerns add another layer. The Siang valley lies in a seismically active Himalayan region, raising questions about the safety of a massive dam and reservoir amid earthquakes, landslides and extreme rainfall. Opponents also fear damage to forests, river ecosystems and agricultural systems. These concerns require rigorous technical assessment; they should not be treated as proof that a disaster is inevitable. Equally, they cannot be dismissed without transparent environmental and social studies.

Why Have The Protests Turned Volatile?

The immediate flashpoint is the pre-feasibility survey. For the administration, the work is necessary to establish whether the project is technically viable. For opponents, allowing survey teams into affected areas risks making the dam appear inevitable before residents’ objections have been addressed. Protesters have demanded a halt to the studies, the withdrawal of security forces and meaningful consultations with local communities. The government, meanwhile, has stressed the project’s strategic importance and said the survey does not amount to final approval for construction.

Tensions rose after confrontations in early October, when protesters and security personnel gave differing accounts of violence and injuries. Four protesters were detained under the Arunachal Pradesh Unlawful Activities (Prevention) Act, 2014, and the Upper Siang administration subsequently restricted gatherings. On October 24 and 25, protests in Pasighat turned violent, with police reporting damage to an NHPC office, a police station and politicians’ residences, as well as injuries to security personnel. Chief Minister Pema Khandu expressed concern and offered to meet groups for talks.

The Siang project now stands at the intersection of two competing ideas of security: the state’s concern about water, energy and China, and local communities’ concern about land, culture and the right to shape their own future. The pre-feasibility exercise may establish whether the dam can be built, but it cannot, by itself, resolve whether it should be. That answer will depend not only on engineering and strategic calculations, but also on transparent assessments, credible consultation and whether the people most likely to bear the cost believe they have been heard.