The Siang Upper Multipurpose Project: India's Answer to China's Mega Dam, and Why Locals Are Protesting, Explained
Arunachal Pradesh wants to build an 11,200 MW dam on the Siang river to counter China's giant dam upstream. The local Adi community fears losing land and homes. Here is what the project is, why it matters, and where the protests and talks stand in October 2026.
On the map, it is a dam. In the politics of the eastern Himalayas, it is much more. The proposed Siang Upper Multipurpose Project (SUMP) in Arunachal Pradesh is India's planned response to a massive Chinese dam upstream on the same river. But for the Adi people who live along the Siang, it is a threat to their homes, land and way of life. Here is the story, and where it stands in October 2026.
The 60-second version
- What: A proposed 11,200 MW dam and large reservoir on the Siang river in Arunachal Pradesh.
- Cost: Public estimates range from about Rs 1.13 lakh crore to Rs 1.5 lakh crore.
- Why: To counter China's mega dam on the Yarlung Tsangpo upstream, which flows into India as the Siang.
- The opposition: Sections of the Adi community fear displacement and have protested even preliminary studies.
- The latest: On 13 October 2026, CM Pema Khandu agreed in principle to reduce security forces and withdraw FIRs against protesters.
The China factor
The Siang begins in Tibet as the Yarlung Tsangpo, then enters Arunachal Pradesh and becomes the Brahmaputra in Assam. China is building an enormous hydropower project on the river near the border.
Chief Minister Pema Khandu has framed the Siang project as a defensive necessity. He has argued that a large Indian reservoir could absorb sudden water releases from China and secure India's water flows, and has asked protesters to consider: what if China suddenly releases water? In late September 2026, he said the project should be seen not as a conventional hydropower scheme but as a national project with strategic and security implications.
Why the Adi community objects
The Siang valley is the homeland of the Adi people. A dam of this scale would submerge land along the river. Protesters fear:
- Displacement from villages and ancestral land.
- Loss of farmland and community forests.
- Damage to the river, central to Adi culture and livelihoods.
- Seismic risk in one of the most earthquake-prone regions in the world.
Protests have targeted even the pre-feasibility survey, and heavy security deployment in the valley, along with police cases against protesters, has deepened mistrust.
Not everyone is opposed
Support is not zero. In June 2026, 110 households from Geku in Upper Siang district signed an agreement backing the pre-feasibility report, which the government cited as a sign that opinion is divided.
The October 2026 olive branch
On 13 October 2026, Khandu met the ABK Youth Wing and the Adi Students' Union (AdiSU Apex). He agreed in principle to:
- Reduce security personnel deployed in the Siang valley.
- Withdraw FIRs registered during the protests.
He has also said his government will not take the project beyond the feasibility stage without completing the Preliminary Feasibility Report, which he expects to take about three months (November to January), followed by public consultations.
What to watch next
- The feasibility report due in early 2027.
- Withdrawal of FIRs and forces, and whether trust improves.
- Compensation and rehabilitation terms, if the project proceeds.
- China's dam progress, which will shape India's urgency.
The Siang project sits where national security, development and indigenous rights collide. How Arunachal handles the next few months will decide whether it becomes a model of consultation or another bitter dam conflict.
This article is based on official statements and public reporting. Cost estimates vary across sources.
Frequently asked questions
›What is the Siang Upper Multipurpose Project?
The Siang Upper Multipurpose Project (SUMP) is a proposed large dam and reservoir on the Siang river in Arunachal Pradesh. It is planned at about 11,200 MW of hydropower capacity, along with a large water storage reservoir. Cost estimates in public reporting range from about Rs 1.13 lakh crore to Rs 1.5 lakh crore.
›Why does India want to build the Siang dam?
The Siang is the Indian name for the Yarlung Tsangpo, which flows from Tibet. China is building a very large hydropower project on the river upstream. Arunachal Chief Minister Pema Khandu argues that a large Indian reservoir would act as a buffer against sudden water releases or flow changes from China, and calls the project a national project with strategic and security implications.
›Why are local people protesting the Siang project?
Members of the Adi community, whose villages and farmland lie along the Siang, fear displacement, loss of ancestral land, and damage to the river ecosystem. Protests have opposed even the preliminary studies, and security deployments and police cases against protesters have added to tensions.
›What did Pema Khandu promise in October 2026?
On 13 October 2026, after meeting Adi youth and student groups, Khandu agreed in principle to reduce security personnel in the Siang valley and withdraw FIRs filed during the protests. He has said the project will not move beyond the feasibility stage without completing the preliminary feasibility report and public consultations.