Quick answer: The Siang Upper Multipurpose Project (SUMP) is a proposed storage dam of about 11,200 MW on the Siang river in Arunachal Pradesh, meant largely to buffer India against China’s mega dam upstream. In October 2026 it was back in the news as protests by the Adi community, who fear loss of land and heritage, turned violent in Pasighat.
Why the Adi tribe and the Siang project are in the news
Anti-dam groups called a 12-hour bandh in the Siang valley on 23 October 2026. EastMojo, citing the Arunachal Times, reported that five women from Geku were hospitalised after police fired tear gas. Protesters want surveys halted, Central Armed Police Forces withdrawn and detained activists freed.
ThePrint reported on 27 October 2026 that a mob set fire to the NHPC office in Pasighat. NHPC, which is preparing the pre-feasibility report, has still not finalised the dam site.
Key facts about the Siang Upper Multipurpose Project
- Capacity: about 11,200 MW in recent reports (some reports give 11,000 MW or more), which would make it India’s largest hydropower project.
- Developer: NHPC, tasked with the pre-feasibility report (PFR).
- Candidate sites: Uggeng, Dite Dime and Parong in Siang and Upper Siang districts, named in the draft PFR submitted to the Jal Shakti Ministry and Central Water Commission on 30 December 2022.
- History: declared a national project in 2008. In 2017 NITI Aayog proposed merging the earlier Phase I and Phase II into one storage project.
- Main purpose: Jal Shakti officials told ThePrint the aim is storage and flood moderation, with power as a by-product. The reservoir could absorb sudden surges if water is released or a dam fails upstream.
Why India wants the dam: China’s Medog project
China began building a mega hydropower project on the lower Yarlung Tsangpo in Medog (Motuo) county, Nyingchi prefecture, Tibet, in July 2025, with Premier Li Qiang at the ground-breaking. It is reported at about 60,000 MW and close to 1.2 trillion yuan in cost, near the Line of Actual Control. India fears sudden releases or lean-season cuts from such a reservoir; SUMP is pitched as counter-storage to absorb those shocks.
Course of the Siang–Brahmaputra
| Stretch | Name of the river | Key point |
|---|---|---|
| Tibet | Yarlung Tsangpo | Flows east across southern Tibet, then turns sharply around the Namcha Barwa massif |
| Arunachal Pradesh | Siang (Dihang) | Enters India in Upper Siang; reaches the plains near Pasighat |
| Assam | Brahmaputra | Joined by the Dibang and Lohit near Sadiya, after which it is called the Brahmaputra |
| Bangladesh | Jamuna | Joins the Ganga (Padma) before reaching the Bay of Bengal |
The Adi people: what to know
- Where they live: mainly in the Siang belt, that is Siang, East Siang, Upper Siang and West Siang districts, with smaller groups in Lower Dibang Valley, Lohit, Shi Yomi and Namsai. They are not concentrated in Lower Dibang Valley alone, as some notes suggest.
- Village council: the Kebang, a traditional self-governing body that settles disputes and runs village affairs. The Adi Bane Kebang is the community’s apex body.
- Faith: most Adis traditionally follow Donyi-Polo, the worship of the Sun (Donyi) and Moon (Polo); the priest or shaman is called the Miri.
- Festivals: Solung, a five-day agricultural festival in early September after sowing, and Aran (Unying), which marks the start of the new year and the farming season.
- River bond: the community reveres the Siang as a mother and protector. Villages grow paddy and pineapple on its banks.
Major tribes of Arunachal Pradesh
| Tribe | Main area | Notable festival |
|---|---|---|
| Adi | Siang belt (Pasighat, Yingkiong) | Solung, Aran |
| Galo | West Siang (Aalo) | Mopin |
| Nyishi | Papum Pare, Kurung Kumey, East Kameng | Nyokum |
| Apatani | Ziro valley, Lower Subansiri | Dree, Myoko |
| Monpa | Tawang, West Kameng | Losar |
| Idu Mishmi | Dibang Valley | Reh |
| Tai Khamti | Namsai | Sangken |
Exam angle: how NDA, CDS and CAPF can ask this
- Questions on the names of the Brahmaputra in Tibet, Arunachal, Assam and Bangladesh, and on its tributaries such as the Dibang and Lohit, are common in NDA and CDS geography.
- Tribe–state–festival matching (Adi–Solung, Apatani–Dree, Monpa–Losar) is regular static GK.
Practice MCQs
Q1. The Siang river is known as what in Tibet?
(a) Sutlej (b) Yarlung Tsangpo (c) Lohit (d) Subansiri
Answer: (b) — the Yarlung Tsangpo becomes the Siang in Arunachal Pradesh.
Q2. Which organisation is preparing the pre-feasibility report of the Siang Upper Multipurpose Project?
(a) NTPC (b) NEEPCO (c) NHPC (d) SJVN
Answer: (c) — NHPC is conducting the surveys.
Q3. “Kebang” refers to:
(a) a dance of the Monpas (b) the village council of the Adis (c) a Buddhist monastery (d) a type of rice beer
Answer: (b) — Kebang is the traditional Adi village council.
Q4. Solung is a festival of which tribe?
(a) Apatani (b) Nyishi (c) Adi (d) Monpa
Answer: (c) — Solung is the main agricultural festival of the Adis.
Frequently asked questions
What is the Siang Upper Multipurpose Project?
It is a proposed storage dam of about 11,200 MW on the Siang river in Arunachal Pradesh, planned mainly for water storage and flood moderation, with power as a by-product. NHPC is preparing its pre-feasibility report.
Why are the Adi people opposing the Siang dam?
They fear the dam will submerge villages, farmland and ancestral land, and damage their culture and the river they revere as a mother. They also object to the deployment of security forces for the surveys.
Where do the Adi people live?
The Adis live mainly in the Siang, East Siang, Upper Siang and West Siang districts of Arunachal Pradesh, with smaller groups in Lower Dibang Valley and nearby districts.
How is the Siang project linked to China?
China began building a dam of about 60,000 MW on the Yarlung Tsangpo in Medog county in July 2025. The Siang project is meant to give India storage to absorb sudden changes in river flow from upstream.
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Sources: ThePrint, EastMojo, Down To Earth, EastMojo on Solung. Facts as reported up to 1 November 2026.
Featured image background: Anu007bora / Wikimedia Commons, CC BY-SA 4.0.
