Why the Siang Project is important to India as China builds the Brahmaputra mega dam and why Arunachal locals are rioting

India’s 11,200 megawatt Siang Upper Multipurpose Project (SUMP) in Arunachal Pradesh is about more than just generating electricity.

For New Delhi, the project is likely a strategic hedge against China’s massive hydroelectric development upstream of the Yarlung Tsangpo River in Tibet.

But the proposal sparked strong local opposition, with protests turning violent in October over fears of displacement, loss of ancestral land and environmental damage.

Why China’s dam plans concern India?

Fresh research by Chinese scientists has added another dimension to the debate. Researchers from the Chinese Academy of Sciences and Yunnan University warned that runoff in the Yarlung Tsangpo could increase over the course of this century, which could increase the frequency of high-flow events, including flooding.

According to the South China Morning Post, researchers reconstructed the river’s runoff history from 1325 to 2020 using tree-ring data from the southeastern Tibetan Plateau.

The river flows east through Tibet before turning south through the Himalayas into Arunachal Pradesh, where it is known as the Siang. It then flows into Assam, which forms the main channel of the Brahmaputra, before continuing into Bangladesh.

China is developing an announced 60,000 MW Medog hydroelectric project on the Yarlung Tsangpo. Its location upstream of India has raised concerns about how dam operations could affect water flows downstream, including the possibility of sudden releases or reductions in flow during dry periods.

How Project Siang could help India

The proposed SUMP is designed to produce electricity while storing and regulating water. Arunachal Pradesh Deputy Chief Minister Chowna Mein said in October that the project should not be compared to China’s Medog project in terms of power generation capacity alone.

According to data cited by Mein, SUMP could provide around 9.2 billion cubic meters of live storage, compared to an estimated 5.5 billion cubic meters for the Chinese project. Live storage refers to the portion of a reservoir that is available to manage water releases.

The state government says the reservoir could help regulate water flows and reduce flood risks in the Siang basin and downstream regions of Arunachal Pradesh and Assam.

By retaining some of the inflowing water and releasing it in a controlled manner, the reservoir can help mitigate peak flows under appropriate conditions.

Read also | China’s $168 billion Brahmaputra Dam is facing fresh concerns over the risk of flooding

The project could also add significant hydro capacity to India’s electricity supply, supporting the Northeast’s energy needs and creating employment and infrastructure opportunities.

In June 2025, Union Minister Kiren Rijiju described the project as a strategic imperative for India’s national security, linking it to China’s hydroelectric plans, as reported by News18.

Why local communities oppose the dam

For the people of the Siang Valley, the project raises immediate concerns for their homes, land and way of life.

Members of the Adi indigenous community and other local groups fear the proposed dam could flood ancestral land, displace villages, damage the local environment and threaten traditional livelihoods and cultural heritage.

The opposition also focused on preliminary survey work for the project’s preliminary feasibility report. The protesters demanded that the survey process be halted and that affected communities be consulted before the project moves forward.

In October 2026, demonstrations escalated into clashes in parts of Arunachal Pradesh.

According to reports, protests in Pasighat turned violent on October 23, with police reporting stone pelting, injuries to personnel and damage to both public and private property.

The Siang Upper Multipurpose Project has become a test of how India balances strategic interests with local interests.

China’s upstream dam plans have sharpened India’s focus on water storage and river management.