A study by Chinese geologists has found that an active fault line beneath the world’s largest hydropower project on the Brahmaputra River in Tibet could affect its structural stability, raising questions over Beijing’s repeated claims that it would help prevent disasters in the region.

The project is close to the Indian border in Arunachal Pradesh.

The scientists said a fracture in the Earth’s crust in the eastern Himalayan region could significantly affect the structural integrity of the massive hydropower project’s infrastructure, the Hong Kong-based South China Morning Post reported on Thursday.

In a paper published last month in the Chinese-language journal Sedimentary Geology and Tethyan Geology, the researchers said the Paizhen Fault, which has been highly active since the Pleistocene, or Ice Age, “will have a major impact on the structural stability and construction of nearby structures, including dams, roads, bridges and tunnels, as well as the reservoir area.” The study was supervised by the state-owned China Geological Survey.

According to the researchers, prolonged fault activity has fractured and weakened the surrounding rock formations, making the foundations and structural stability of nearby engineering projects more vulnerable to damage.

“The Paizhen area is located within the reservoir area of the Yarlung Tsangpo downstream hydropower station,” the paper said.

China refers to the Brahmaputra as the Yarlung Tsangpo.

China formally began construction of the $167.8-billion dam on the Brahmaputra in Tibet last July.

Expected to generate more than 300 billion kWh of electricity annually, the dam is projected to meet the annual power needs of more than 300 million people.

The dam is being built in a massive gorge in the Himalayas where the Brahmaputra makes a sharp U-turn before flowing into Arunachal Pradesh and later Bangladesh.

China went ahead with the project despite enormous engineering challenges, as the site lies along a tectonic plate boundary that experiences frequent earthquakes.

The Tibetan Plateau, often described as the “roof of the world”, is prone to periodic earthquakes because of the movement of tectonic plates beneath it.

The researchers cited the magnitude 6.9 earthquake that struck Milin in Tibet in 2017 near the northern end of the fault as evidence that the fault remains seismically active.

“Under regional seismic action, landslides and collapses can easily be induced, threatening the safety of engineering facilities and personnel,” they said.

The recent findings add to concerns over the project’s structural safety, with the researchers urging engineers to reinforce vulnerable slopes and install retaining structures to reduce the risk of landslides and collapses.

However, China has consistently sought to allay concerns over the safety of the project. Beijing has repeatedly claimed that the project meets the highest industry standards and would help prevent disasters in the region.

An official statement issued in December 2024 said the hydropower project was safe and prioritised ecological protection.

“Through extensive geological explorations and technical advancements, a solid foundation has been laid for the science-based, secure, and high-quality development of the project,” it said.

In July last year, a Chinese Foreign Ministry spokesperson said China was highly responsible in developing cross-border rivers and had rich experience in building hydropower projects.

In planning, designing and constructing the hydropower project in the lower reaches of the river, China strictly followed the highest industry standards while protecting the ecological environment in an all-round way, the spokesperson had said.

He also maintained that the project would help prevent disasters along the river and would not have a negative impact on downstream regions.

The Brahmaputra flows across the Tibetan Plateau, carving out the world’s deepest canyon before entering India.

The study was conducted by geologists from the Chengdu University of Technology, the Civil-Military Integration Centre of the China Geological Survey, and the Middle Yarlung Zangbo River Natural Resources Observation and Research Station, according to the South China Morning Post.

The researchers said Pai (also called Paizhen) village in Tibet, where construction is underway, lies in the Himalayan seismic belt, one of the most earthquake-prone regions in China and neighbouring regions, where intense seismic activity has developed along the Yarlung Tsangpo.

“Its records of Quaternary tectonic activity provide an important basis for exploring the structural stability of nearby projects,” the paper said.

The Paizhen Fault is part of a network of tectonic faults in the eastern Himalayan region created by the collision of the Indian and Eurasian tectonic plates. The researchers said the fault has remained active since the Early Pleistocene and continues to exhibit strong activity during the present Holocene epoch. Dating of ancient lake sediments suggests the fault remained active as recently as 9,500 years ago.

Published – July 12, 2026 10:26 pm IST

File photo of Chinese Foreign Ministry spokesperson Mao Ning
| Photo Credit: AP

China on Friday (December 27, 2024) defended its plan to build the world’s largest dam on the Brahmaputra river in Tibet, saying the project will not “negatively affect” lower riparian states and that safety issues have been addressed through decades of studies.

Chinese Foreign Ministry spokesperson Mao Ning played down apprehensions about the massive project to dam the Brahmaputra river, which is called Yarlung Zangbo in Tibet. The project estimated to cost around ₹137 billion is located in the ecologically fragile Himalayan region, along a tectonic plate boundary where earthquakes occur frequently.

Ms. Mao said China carried out in-depth studies for decades and took safeguard measures.

China has always been responsible for the development of cross-border rivers, Ms. Mao told a media briefing here in response to a question on the concerns related to the dam.

She said the hydropower development there has been studied in depth for decades, and safeguard measures have been taken to ensure the project’s security and ecological environment protection.

“The project will not negatively affect the lower reaches,” she said referring to the concerns in India and Bangladesh which are the lower riparian states.

“China will continue to maintain communication with countries at the lower reaches through existing channels and step up cooperation on disaster prevention and relief for the benefit of the people by the river,” she said.

She said China’s hydropower development in the lower reaches of the Yarlung Zangbo river aims to speed up the development of clean energy and respond to climate change and extreme hydrological disasters.

China on Wednesday approved the construction of the world’s largest dam, stated to be the planet’s biggest infra project, on the Brahmaputra river in Tibet close to the Indian border, raising concerns in India and Bangladesh.

The hydropower project will be built in the lower reaches of the Yarlung Zangbo river, the Tibetan name for the Brahmaputra, an official statement here said.

The dam will be built at a huge gorge in the Himalayan reaches where the Brahmaputra river makes a huge U-turn to flow into Arunachal Pradesh and then to Bangladesh.

Ms. Mao said China’s hydropower development in the lower reaches of the Yarlung Zangbo river aims to speed up the development of clean energy and respond to climate change and extreme hydrological disasters.

The total investment in the dam could exceed one trillion yuan ($137 billion), which would dwarf any other single infrastructure project on the planet, including China’s own Three Gorges Dam which is regarded as the largest in the world, the Hong Kong-based South China Morning Post reported on Thursday.

China has already operationalised the $1.5 billion Zam Hydropower Station, the largest in Tibet in 2015.

The Brahmaputra dam was part of the 14th Five-Year Plan (2021-2025) and National Economic and Social Development and the Long-Range Objectives Through the Year 2035 adopted by Plenum, a key policy body of the ruling Communist Party of China (CPC) in 2020.

Concerns arose in India as the dam besides empowering China to control the water flow could enable Beijing to release large amounts of water flooding border areas in times of hostilities because of its size and scale.

India too is building a dam over Brahmaputra in Arunachal Pradesh.

India and China established the Expert Level Mechanism (ELM) in 2006 to discuss various issues related to trans-border rivers under which China provides India with hydrological information on the Brahmaputra and Sutlej rivers during the flood seasons.

Data sharing of trans-border rivers figured in the talks between India, China Special Representatives (SRs) for border questions which National Security Advisor (NSA) Ajit Doval and Chinese Foreign Minister Wang Yi held here on December 18.

The SRs provided positive directions for cross-border cooperation and exchanges including data sharing on trans-border rivers, a statement by the Ministry of External Affairs said.

The Brahmaputra dam presents enormous engineering challenges as the project site is located along a tectonic plate boundary where earthquakes occur.

The Tibetan plateau, regarded as the roof of the world, frequently experiences earthquakes as it is located over the tectonic plates.