The inauguration of a mega-dam on a Chinese river has become the latest flashpoint in South Asia’s turbulent politics. Marking a pivotal moment in regional hydro-politics, this $167 billion project will increase China’s control over trans-boundary water flows, unsettling downstream neighbours like India.

Located on the eastern rim of the Tibetan plateau, the Yarlung Tsangpo River, is set to become the world’s largest hydro-power facility, tripling the capacity of China’s famous Three Gorges Dam.

But for lower riparian countries like India and Bangladesh, the Yarlung Tsangpo is a vital lifeline for their agriculture. After exiting Tibet, it becomes the Brahmaputra River, flowing through India’s northeastern states of Arunachal Pradesh and Assam before entering Bangladesh.

Due to concerns largely raised by India, China delayed the project, known as the Motuo Hydropower Station, to carry out intensive scientific evaluations regarding geological stability, the ecological environment and water resource rights of lower riparian countries. Finally, the dam was approved in December 2024. 

According to Chinese experts, the dam can reduce chances of flooding but according to the Indian side, no mitigation measures have been taken. Responding to New Delhi’s objections five years ago, China’s foreign ministry asserted its “legitimate right” to dam the river but promised to consider downstream impacts.

Indian reservations and strategic anxiety
 

After its launch, Chinese media hailed the Motuo Dam as the “project of the century”. Domestically, it’s being promoted as a triumph for energy security, economic growth in Tibet, and climate resilience. 

Despite Beijing’s assurances of rigorous environmental safeguards, India remains unconvinced. The fact remains that China gains considerable strategic leverage with this venture.

According to a 2020 report by the Lowy Institute, an Australian-based think tank, “Control over these rivers [in the Tibetan plateau] effectively gives China a choke-hold on India’s economy.” 

Earlier this year, Pema Khandu, Chief Minister of Arunachal Pradesh, warned that such a colossal dam, just 50 kilometres from the Indian border, could reduce water flow by up to 80 percent and potentially flood downstream regions in Arunachal and Assam. 

Although India has not yet conducted formal hydrological modelling to support these claims, it possesses the technical capacity to do so.

For now, New Delhi’s concerns appear to be driven more by strategic considerations than scientific assessments, especially given the dam’s proximity to a disputed region and its unprecedented scale.

Khandu also expressed fears that China could wield the dam as a “water bomb,” implying it could be deployed as a geopolitical weapon in times of conflict.

China-India Relations

Fears that China may “weaponise” water have spurred India into action. New Delhi is accelerating its own hydropower plans, including the proposed 10 GW Siang dam project meant to buffer Chinese influence.

But though India considers Arunachal state [where the Brahmaputra flows through] an integral part of its territory, China claims it as part of Southern Tibet and objects to any Indian infrastructure projects there, creating room for more controversy.

Ironically, the final greenlighting of the Motuo Dam came just as tensions in the Galwan Valley appeared to be easing, suggesting water infrastructure is now part of a broader strategic calculus.

China has previously withheld river data from India, most notably during the 2017 Doklam border standoff, a subtle reminder that water can be as powerful a tool as military force.

Since the deadly Galwan Valley clash in 2020, trust between Beijing and New Delhi has remained elusive and recurring military standoffs along the Line of Actual Control (LAC) in the last few years have strained bilateral ties.

Even though Sino-Indian diplomatic engagement remains stable, strategic rivalry and unresolved issues persist. Without a binding water-sharing treaty, existing tensions along the LAC can get easily stirred up, and China would have complete upstream control. 

Lessons from the Indus Waters Treaty

This emerging scenario echoes the long-standing water disputes between India and Pakistan under the Indus Water Treaty (IWT).

Brokered by the World Bank in 1960, the IWT gave India control over eastern rivers Sutlej, Beas and Ravi, and Pakistan control over the western rivers, Indus, Jhelum and Chenab.

Despite surviving multiple wars, India recently put the treaty in abeyance though no such legal provision exists in the agreement. In protest, Pakistan said that this would be considered an ‘act of war’. Meanwhile, the Hague-based Permanent Court of Arbitration has unanimously decided that the treaty holds and it cannot be unilaterally dissolved.

Blaming Islamabad for a militant attack in Kashmir this April without credible evidence, India suspended key provisions of the IWT and threatened to restrict water flows. Such a move severely impacts Pakistan’s economy, where agriculture accounts for 24 percent of GDP.

By asserting unilateral upstream control outside a binding legal mechanism, India may have set a precedent—one that China could now be tempted to follow.

Once completed, the Motuo dam will give China uncontested upstream control over the Brahmaputra, in the absence of any formal treaty or arbitration mechanism, leaving India exposed and diplomatically constrained.

Ironically, the Indus Waters Treaty—long criticised in India as an outdated concession to Pakistan—now appears to be the kind of legal framework New Delhi may come to desire in its dealings with Beijing.

Can China’s new dam improve regional water security?

While New Delhi views the Motuo Dam as a threat, Islamabad is more likely to view Beijing’s hydro-influence as a stabilising force.

The deep Sino-Pakistani cooperation evident in successful joint ventures like the Karot and Neelum-Jhelum hydropower plants offers a constructive model for upstream-downstream coordination, in stark contrast to the fraught water-sharing dynamics between India and Pakistan.

Looking ahead, China’s hydropower leverage could serve as a strategic counterweight to potential Indian attempts to disrupt water flows to Pakistan. 

Moreover, just as China routinely objects to Indian infrastructure development in Arunachal Pradesh, Pakistan has long opposed Indian dam construction on shared rivers, citing violations of the Indus Waters Treaty. These parallel patterns highlight a growing regional trend: water as a tool of geopolitical contestation.

Despite holding upstream control over several critical rivers, China has no legally binding water-sharing agreements with any of its downstream neighbours. Whether it would entertain such a treaty with India remains uncertain. Still, both countries could benefit from formalising a cooperative mechanism for the Brahmaputra.

Bangladesh, too, has voiced concern. In February, Dhaka formally requested details about the Motuo dam but reportedly received no official response. Chinese officials later assured Bangladesh during a visit that the project was a run-of-the-river scheme and would not involve water diversion.

In late March, Bangladesh’s interim leader, Muhammad Yunus, visited Beijing, and the two countries reaffirmed existing arrangements for the sharing of hydrological data.

Given its downstream location, Bangladesh’s inclusion in any future Brahmaputra agreement would be logical. However, Dhaka’s warming ties with Beijing – and recent frictions in India-Bangladesh relations – may make New Delhi reluctant to engage in a tripartite framework.

The time has come for India to rethink its approach to water diplomacy. Rather than dismantle the Indus Waters Treaty, it should strengthen that legacy and pursue a similar agreement with China.

A Brahmaputra Convention could transform a looming crisis into a foundation for regional stability, turning rivers into shared resources rather than contested fault lines.