China’s $167-billion hydropower project in Tibet could give Beijing greater control over Brahmaputra, a river that sustains millions downstream. India fears changes to water flows, flood risks and ecological damage, besides the strategic implications of a mega-project near its border.
The Brahmaputra is more than a river for India. It sustains farms, fisheries, communities and ecosystems across the Northeast. But before it enters India, the river flows through Tibet, where China is building what is expected to become the world’s largest hydropower project.
The project, on the lower reaches of the Brahmaputra, has raised concerns in New Delhi over water security, disaster risks and Beijing’s growing leverage over a transboundary river. Construction began in July 2025, bringing a long-standing concern into sharper focus.
Here is why the dam matters for India.
What is China building, and where?
The Yarlung Tsangpo originates in Tibet and flows eastwards before making a dramatic U-turn around the Namcha Barwa massif. It then cuts through a deep gorge before entering Arunachal Pradesh as the Siang, which subsequently becomes the Brahmaputra in Assam and flows into Bangladesh.
China’s project is planned for this steep, mountainous stretch, where the river drops roughly 2,000 metres over 50 km, creating enormous potential for hydropower generation.
The project is expected to comprise five cascade hydropower stations, with a combined installed capacity exceeding 60,000 megawatts. It could generate around 300 billion kilowatt-hours of electricity annually, more than three times the designed annual generation of China’s Three Gorges Dam.
Beijing has presented the project as part of its clean-energy ambitions and economic development plans for Tibet. But its location, close to the Indian border, makes it a matter of strategic concern for New Delhi.
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Why is India worried about water security?
The biggest concern is not simply that China is building a dam, but that it controls the river upstream of India.
An upstream country can influence the timing and volume of water flowing downstream through reservoir operations, even if it cannot permanently stop a major river. Filling reservoirs, storing water during particular seasons or releasing it in large quantities can affect downstream flows.
A Reuters report published in August 2025, citing an Indian government analysis, said the project could potentially enable China to divert up to 40 billion cubic metres of water. Under certain assumptions, flows at a key border point could fall by as much as 85 per cent during dry months.
These are estimates of potential impacts, not evidence that such a reduction will occur. The precise consequences remain uncertain because China has not publicly provided enough detailed technical information for India to independently assess the project’s operations.
The stakes are significant. Reduced flows during dry periods could affect agriculture, fisheries and local water availability. Changes in the timing of releases could also complicate water management in Arunachal Pradesh and Assam.
However, the Brahmaputra receives substantial water from rainfall and tributaries within India. The scale of any downstream impact would therefore depend on the dam’s design, operating practices, seasonal conditions and the river’s wider hydrology.
Could China use the dam as a strategic weapon?
The concern extends beyond water availability. India and China have a contested border and a history of military tensions. A mega-project on a river entering India from Chinese-controlled territory introduces another dimension to this relationship.
In a crisis, uncertainty over reservoir operations and water releases could complicate India’s security calculations. Sudden releases during heavy rainfall could potentially worsen downstream flooding, while reduced releases could aggravate water shortages during dry periods.
This does not mean China can simply switch off the Brahmaputra or that it intends to weaponise the river. The dam’s actual capacity to alter flows will depend on its design and operation. Nevertheless, the absence of transparency creates a strategic problem: India cannot confidently assess the risks without reliable information from Beijing.
The issue is compounded by the lack of a comprehensive water-sharing treaty between India and China that allocates the Brahmaputra’s waters. The two countries have mechanisms for discussing transboundary rivers, but these do not provide the same certainty as a binding agreement on water allocation and dam operations.
What about earthquakes, floods and the environment?
The project is being constructed in a geologically active part of the eastern Himalayas, where earthquakes, landslides and extreme rainfall pose significant engineering challenges.
In July 2026, a report on research by Chinese geologists raised concerns about an active fault beneath the project site, highlighting potential risks to infrastructure stability and surrounding slopes. The finding has renewed questions about how a project of this scale can withstand the region’s geological hazards.
A major structural failure or an uncontrolled release of water could have serious consequences for communities downstream. However, such outcomes are risks to be assessed, not inevitable consequences of construction.
There are also environmental concerns. Large hydropower projects can alter sediment transport, river ecology and habitats. Changes in sediment flows could affect agriculture and ecosystems downstream, while construction could disturb fragile landscapes in Tibet.
China maintains that its hydropower development has undergone scientific assessment and will not adversely affect downstream countries. But without detailed information and independent scrutiny, India has limited means of verifying these assurances.
How is India responding?
New Delhi has raised its concerns through diplomatic channels and has called for transparency, consultation and the protection of downstream interests.
India has also been seeking hydrological data and technical details about China’s upstream projects. The absence of regular river-flow information makes it harder to forecast floods and prepare for sudden changes in water levels.
Another response is the proposed Siang Upper Multipurpose Project in Arunachal Pradesh. The project is intended to provide hydropower, water storage and a measure of protection against potential changes in upstream flows. It could also help manage flood risks.
But building another giant dam is not without costs. The proposed project faces opposition from local communities concerned about displacement, submerged villages and damage to their land and livelihoods. It also raises its own environmental and seismic safety questions.
What happens next?
The central challenge for India is to prepare for the dam’s possible consequences without treating the worst-case scenario as a certainty.
Reliable hydrological data, advance notification of reservoir operations, technical consultations and cooperation on disaster management would help reduce uncertainty. India will also need to strengthen flood forecasting and emergency preparedness across the Brahmaputra basin.
Ultimately, the Yarlung Tsangpo project is not just an energy infrastructure story. It is a test of whether two Asian powers sharing a vital river can build enough trust to manage its risks.
For India, the question is not whether China should generate hydropower, but whether a project of unprecedented scale can proceed without compromising the security and livelihoods of millions living downstream.