The 11,200 MW Siang Upper Multipurpose Project (SUMP) in Arunachal Pradesh, planned as a strategic buffer against China’s mega-dam on the Yarlung Tsangpo, has drawn protests from local Adi communities. Protests turned violent in Pasighat on 23 October 2026.

• Why India wants it: China is building a 60 GW mega-dam on the Yarlung Tsangpo, which becomes the Siang in Arunachal Pradesh and the Brahmaputra in Assam. India fears China could divert flows or release water suddenly, causing drought or floods downstream.
• China’s project: Five cascading power stations over a fall of about 2,000 metres in 50 km. Beijing says it will not harm downstream countries but has declined to share engineering details.
• Data gap: China has agreed only to share hydrological data on humanitarian grounds in emergencies.
• On the ground: Survey teams are guarded by security forces, and the Unlawful Activities (Prevention) Act has been used against activists, which feeds local fear of land loss.
• Protesters’ demands: Halt the pre-feasibility survey, release detained activists, reinstate suspended village headmen and withdraw security forces.
• Wider pattern: Protests also face the Subansiri Upper Hydroelectric Project.

• Limited control: The Brahmaputra in Assam and Bangladesh receives most of its water from monsoon rain and tributaries downstream of the Tibetan Plateau, so China cannot control its total flow in India.
• But near the border: Chinese actions would matter most close to the border.
• Planning problem: SUMP needs information on the mega-dam’s operations and downstream inflows. Planners have thought of keeping the SUMP reservoir at about 70% to absorb surges, but the protection possible without advance warning is unclear.

• Strategic buffer: Storage can regulate flows and moderate floods, and supports India’s water security.
• Hydropower: It would be one of India’s largest hydropower projects.
• Rights of local people: The case tests whether national needs can be met without overriding local land and community rights.
• Water diplomacy: Operating SUMP safely depends on diplomacy with China.

• Trust deficit: Local people fear loss of ancestral land and villages.
• Hazards: The eastern Himalayas are among the world’s most tectonically active and erosion-prone regions.
• Uncertainty over China’s dam: No reliable data on operations.
• Legal compliance: The State must follow all relevant laws, including consent and rehabilitation provisions.