GUWAHATI: A proposed mega dam on the Siang River in Arunachal Pradesh has become the centre of a growing dispute between the government’s water security concerns and local communities’ fears over their land, livelihoods and cultural heritage.
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The 11,200-megawatt Siang Upper Multipurpose Project (SUMP) is being planned against the backdrop of China’s massive hydropower project on the Yarlung Tsangpo River in Tibet, which flows into India as the Siang. While the Centre views the project as a potential safeguard against changes in upstream water flows, sections of the indigenous Adi community are demanding that it be scrapped.
The disagreement has now escalated into protests and clashes, raising questions about how India can address strategic concerns while protecting the interests of communities living along the river.
What is the Siang Upper Multipurpose Project?
The Siang Upper Multipurpose Project is a proposed 11,200-megawatt hydropower and water storage project on the Siang River in Arunachal Pradesh. The state-owned National Hydroelectric Power Corporation (NHPC) has been tasked with conducting pre-feasibility surveys and technical assessments.
The project is intended to generate renewable electricity and provide water storage capacity. According to the government’s position, the reservoir could also help regulate river flows, support flood management and strengthen India’s water security.
However, the project remains contentious, with local residents concerned about the possible submergence of ancestral lands, displacement, environmental damage and the loss of cultural sites associated with the river.
Why does China’s dam project matter?
The Siang River originates in Tibet, where it is known as the Yarlung Tsangpo. It flows eastwards before turning south and entering Arunachal Pradesh as the Siang, also known as the Dihang. The river later joins other rivers to form the Brahmaputra, which flows through Assam and Bangladesh.
In December 2024, China announced plans for a major hydropower project on the Yarlung Tsangpo. Construction began in July 2025 in Medog County, Tibet, according to reports.
The scale and location of the Chinese project have raised concerns in India because it is situated upstream of communities that depend on the river. Changes in the timing or volume of water released downstream could have implications for water management, agriculture and flood preparedness.
The region is also seismically active, adding to concerns about the risks associated with large infrastructure projects in the river basin.
China claims Arunachal Pradesh, which it refers to as Zangnan, as part of southern Tibet. India rejects this claim and maintains that Arunachal Pradesh is an integral and inalienable part of its territory.
How could India’s proposed dam help?
The Centre views SUMP as a potential strategic safeguard against the risks associated with China's control over upstream water infrastructure.
A large reservoir could, in principle, allow India to store water and manage fluctuations in river flows. The government also expects the project to strengthen electricity generation and create economic opportunities in Arunachal Pradesh.
However, the extent to which the project could mitigate risks arising from China's upstream dam would depend on its design, storage capacity, operating arrangements and the actual nature of any changes in water flow. The proposed project should not automatically be viewed as a guarantee against sudden releases or other upstream interventions.
Why are local communities opposing the project?
Sections of the indigenous Adi community, youth leaders and residents of the Siang Valley fear that the proposed dam and reservoir could fundamentally alter their lives.
The concerns extend beyond the potential loss of homes and agricultural land. The river and its surrounding landscape are closely connected to the community’s cultural identity, traditions and ancestral heritage.
Residents also fear damage to the local environment and the disruption of livelihoods that depend on the river and surrounding land.
The Adi Banne Kebang, the community-led apex body spearheading the protests, has demanded that the project be scrapped and its Pre-Feasibility Report (PFR) rejected.
The opposition has continued even as the state government maintains that it will proceed with the feasibility assessment.
How have the protests escalated?
Protests in the Siang Valley have taken place intermittently over the past two years. Tensions escalated last week when demonstrators clashed with police.
According to reports, police fired tear gas shells as protesters pelted stones and set fire to a police station and an office of the NHPC. At least 21 people were arrested.
Authorities said on Tuesday that hundreds of additional security personnel had been deployed in the region following the clashes.
The Arunachal Pradesh government, led by Chief Minister Pema Khandu, has maintained its position on conducting the feasibility assessment for the proposed project. The NHPC is responsible for the pre-feasibility surveys and technical assessments.
The confrontation has brought the concerns of local communities into sharper focus, even as the government considers the project important for national security and energy generation.
