A deep trust deficit is holding back the Siang mega dam in Arunachal Pradesh

China’s rapid construction of a dam just across the border prompted India to propose a massive countermeasure: an 11,000-megawatt dam on the Siang River in Arunachal Pradesh. However, this strategic plan is blocked in a bitter situation with the local indigenous tribes. While the ₹113,000 crore project is supposed to stem devastating seasonal floods, secure India’s water rights and boost the local agricultural economy, it remains stalled. With thousands of families facing displacement, the subcontinent’s largest planned dam cannot move forward until the government addresses a deep trust deficit with people whose ancestral lands are at risk.

Geopolitical threat and powerful Siang

The race to control the waters of the Siang is being driven by massive hydro-engineering projects currently being undertaken by China on the upper reaches of the river in Tibet. This includes the planned 60,000 MW “super dam” in Medog district, located just upstream from the Indian border. This upstream megaproject gives Beijing substantial control over transboundary waterways, posing two serious risks to downstream India: flow disruptions that trigger ecological devastation during dry months, and catastrophic artificial flooding during sudden water releases.

To counter these threats, the Government of India prioritized the Siang Upper Multipurpose Project (SUMP). The initiative consolidates two earlier proposals from the 2013 MoU (6,000 MW Stage 1 and 3,750 MW Stage II) into a single massive storage-type dam near Geku village in Upper Siang District. The primary focus of this project is security, with power generation serving as a secondary benefit. Abhay Kumar Singh, chairman and managing director of NHPC, was quoted in the media as saying that the preliminary investment for the project was around ₹1,13,000 crore and its height would be 280–300 metres.

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The project, designed with an installed capacity of approximately 11,000 MW to 11,200 MW, will generate 47 billion kWh of electricity annually, making it the largest planned hydroelectric project in the subcontinent. The reservoir’s massive storage volume of 9 billion cubic meters serves two key strategic purposes: the creation of early physical “rights of prior use” to strengthen India’s legal claims under international transboundary water law, and the creation of a vital flood protection zone to absorb sudden surges upstream.

Geography of the Siang Basin

To understand the scope of the project, we need to track down the mighty Siang. Known upstream in Tibet as the Yarlung Tsangpo, the river originates in the Chemayungdung Mountains near Mansarovar at an altitude of 5,300 meters. It runs 1,625 km parallel to the Himalayas, intersects the Grand Canyon and enters India near Gelling, where it becomes the Siang. The river flows 197 km to its confluence with its largest right bank tributary, the 170 km long Shiyomi River (formed near Tato by the Shi and Yomi Rivers). It continues for another 86.3 km to the Assam border where it finally joins the Dibang and Lohit to form the Brahmaputra. The watershed is fed by a dense network of smaller streams, including the high-altitude Yar Gyap Chu, which flows through the Mechuka Valley and has deep religious significance for the local Buddhist population.

Orchard economy in jeopardy

Surrounded by the alluvial waters of the Siang River, the fertile delta region serves as the primary economic backbone of Arunachal Pradesh. For generations, the Adi and Galo indigenous communities have cultivated their slopes and valleys through terraced wet paddy fields and diversified agroforestry, earning a steady household income of between ₹4,000 to ₹7,000 per year. Earth, it turns out, is as generous as it is ancient.

According to the state’s Horticulture Policy 2025-35, this generosity has translated into remarkable agricultural milestones, and today Arunachal Pradesh is India’s largest producer of kiwifruit, harvesting more than 7,000 metric tons annually—and the first state to receive official organic certification for the fruit. Its tangerines tell an equally impressive story: second nationally at 84,000 metric tons, prized varieties from Siluk and Dambuk have found their way onto international shelves, including markets in the United Arab Emirates. Meanwhile, the state in major cardamom leads the entire Northeast region with a yield of 4,467 metric tons, a quiet dominance that speaks volumes of what the country and its people are quietly capable of.

However, this prosperity is constantly under threat. During the summer monsoon, the fickle, unregulated currents of the Siang shift, causing severe bank erosion, washing away topsoil and triggering landslides that destroy terraced fields and orchards. Proponents argue that the construction of high-capacity storage reservoirs is a critical defense and economic imperative to prevent these course shifts, ensure irrigation and establish Arunachal Pradesh as a self-sufficient powerhouse.

Clearance above pressure

Despite these potential benefits, local communities remain fiercely opposed to the dam. For the indigenous population, the river represents their very identity. Gegong Apang, a former chief minister and leader of the Adi community of Yingkiong in Upper Siang District, expressed deep concern about the project’s threat to local lives and the fragile ecosystem: “The Siang River is not just a resource, it is the lifeline of our people, our culture and our identity.”

Mr. Apang emphasized that the Adi tribe has a deep sacred respect for the river, calling it “Aane Siang” (Mother Siang).

As protests on the ground have blocked the NHPC from conducting preliminary feasibility studies on all three proposed coordinates (Ugeng, Dite Dime and Parong – although Parong is likely to be avoided due to the Tuting Advanced Landing Ground), the exact number of villages to be submerged remains unknown. Estimates are highly polarized: protest groups put the number of displaced villages at 27, while a former chief minister estimated that up to 300 villages could be affected. This impasse is due to a deep-seated mistrust of the state and central governments, stemming from past corruption in land acquisitions. Because the state relies on the national government for funding, local families are genuinely concerned that their cultivated lands and villages will be acquired or displaced without adequate, legitimate compensation.

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Political will vs. local protest

While organizations such as Siang Indigenous Farmer’s Forum (SIFF) and Adi Banne Kebang (ABK) lead the resistance, other local voices support the development. A venerable senior Buddhist monk from Tawang Monastery, who speaks on condition of anonymity, strongly supports the dam when speaking to this writer. He points to neighboring Bhutan, which shares an almost identical environment. “Bhutan has almost the same ecological ecosystem as Arunachal, but they have built many dams and have uninterrupted electricity. They also sell additional electricity to India to generate considerable income. Opposition to the dam is political and not pro-environment,” says the monk.

Proponents of the project also point to the historical precedent of the Sardar Sarovar project in Gujarat. Although this dam attracted intense protests, it was completed due to the strong political will of the government. Today, it successfully provides drinking water to cities and massive irrigation of agricultural land. Proponents say Arunachal’s mountainous terrain is no barrier to success, as evidenced by Bhutan’s strong financial benefits from similar ecosystems.

The road to reconciliation

Resolving this impasse requires the government to abandon coercive tactics and engage in direct and transparent dialogue with SIFF, ABK and traditional village councils (Kebangs). To build trust, the central government must provide legally binding, transparent guarantees for time-bound resettlement and fair compensation. This must include building modern social infrastructure such as schools and health facilities, along with providing technical training so that local youth can secure long-term, high-value employment in the construction and operation of the project.

By leveraging a strategic combination of state and central leadership, similar to the successful implementation of the Golden Quadrilateral Road Project across the North-East region, the government can transform dissenting demonstrations into consensual campaigns built on genuine trust.

(Dr. Mathew Chandrankunnel, Advisor, JIS University Calcutta, is an author, physicist, philosopher, theologian and Catholic priest whose work includes quantum mechanics, science-religion dialogue and research leadership)