Arrests and a security buildup over the proposed Siang dam expose a dispute over whether valley communities will have a decisive say in a project promoted as a national-security necessity.
How the protests escalated
On October 23, protests against the Siang Upper Multipurpose Project (SUMP) included a 12-hour shutdown in parts of Siang, Upper Siang and East Siang districts. Clashes in Pasighat damaged a police station and an office of state-run hydropower company NHPC; political leaders’ homes were targeted. Police said protesters threw stones and security personnel were injured. Protesters and their supporters also described injuries during police action.
East Siang police said 26 people, including five juveniles, were arrested over the Pasighat violence; six others were detained and eight cases registered. The Arunachal Times reported 30 companies of central forces deployed on October 26; NDTV reported 34 the next day after reinforcements arrived.
What the survey could mean
SUMP is planned as an 11,200-megawatt hydropower and water-storage project on the Siang, which flows from Tibet into Arunachal Pradesh and joins the Brahmaputra system. The Centre declared it a national project in 2008, but that is not approval to build. In September 2026, the state cabinet approved a committee to coordinate a pre-feasibility survey. Chief Minister Pema Khandu said no construction decision had been made and the project’s future depends on the assessment.
A 2025 Mongabay report said the reservoir was then expected to submerge more than 25 villages, including Yingkiong, the Upper Siang district headquarters. The final footprint is unsettled, but families fear losing homes, farmland and places tied to community history. Research describes Adi communities’ ties to land and river through identity, customary governance and spiritual life, not only income or property.
The case for the project
The state cabinet says SUMP could produce electricity, support employment and development, help moderate floods and strengthen water security. Its strategic importance has grown alongside China’s hydropower plans on the Yarlung Tsangpo, which becomes the Siang in India. China began construction of a vast project near Medog in 2025. Indian officials worry upstream infrastructure could affect the timing or volume of downstream flows and say storage in India could provide a buffer.
That does not prove SUMP can neutralise risks from China’s project; its value depends on its eventual design, reservoir capacity and operating rules. Information about downstream effects is limited. Experts have argued that transparency and data-sharing matter more than speculation. The national-security case is a government argument about potential risks and benefits, not a demonstrated result of a dam still under assessment.
Why the survey remains disputed
The government says the survey gathers information and has promised engagement; opponents say it risks proceeding without their consent. Protest groups have demanded a halt to survey work, release of detained activists and withdrawal of security forces. Khandu invited opponents to talks and urged them to make their case peacefully. Some residents may see heavy security and protection for survey work as proof the decision is already made, deepening mistrust despite the state saying it is not.
What happens next
A further shutdown was planned for October 27, with protesters demanding release of those arrested and cancellation of the project. The likely near-term outcome is continued political and legal confrontation, not construction: SUMP remains at the survey stage, officials have invited dialogue, and whether the survey should proceed is unresolved. The government will need to persuade affected communities that their participation can still change the outcome.