Global warming has accelerated the retreat and instability of high-altitude glaciers. Landslides and ice avalanches have triggered the outburst of composite barrier lakes, which has become a common nightmare for South Asian countries such as the Tibetan Plateau and downstream Nepal. In late August, Nepal suffered heavy casualties due to severe glacier collapse and flash floods. After this transnational disaster, Nepal made a strong request to China to share transnational hydrological and glacier data. The appeal point is that insufficient data sharing may hinder their ability to predict and prepare for major disasters.
According to reports, the Brahmaputra Grand Canyon area is located at the tectonic suture where the Indian plate and the Eurasian plate collide strongly. It is an important tectonic zone where the Indian plate and the Eurasian plate collide. It has "one of the highest incidence rates of geological disasters in the world." Geological disasters such as earthquakes, landslides, and collapses are highly active.
It is reported that the planning and estimation of the lower reaches of the Brahmaputra River Hydropower Project (Yaxia Project) has a device capacity of approximately 60 million kilowatts and an annual power generation of approximately 300 billion kilowatt-hours. The annual power generation is approximately three times that of the Three Gorges Power Station, which is equivalent to the UK's annual electricity consumption. After the official start of construction in July 2025, India, as a downstream country, showed extremely high anxiety about water resource security and potential flood and drought threats. In August this year, it asked China to share data on the Brahmaputra River.
But there is another layer to the controversy over the Yaxia Project: What China plans to transform is not an ordinary river valley, but the Brahmaputra Grand Canyon.
A commentary published by Radio France Internationale pointed out that according to the UNESCO World Heritage standards, the Grand Canyon has the conditions to highly meet the four natural heritage standards in terms of special natural landscapes, earth evolution and geological processes, ecological evolution and rare species habitats.
Foreign media pointed out that the biggest controversy about the Yaxia project may not be how much power it can generate, but that it was chosen to start construction in an area with the most sensitive biodiversity in China. The five cascade power stations may fundamentally change the original connectivity of the river.
Data show that the Brahmaputra Grand Canyon National Nature Reserve covers an area of 916,800 hectares, and contains about 13% of China’s vascular plants and about 20% of terrestrial vertebrates.
Chinese officials confirmed that the project will be developed using the method of "cutting corners to straighten them and diverting water through tunnels." This means that the flow, velocity, water temperature and sediment transport of some natural river sections may change accordingly; however, the locations of each cascade dam, water diversion distance and ecological flow arrangements have not yet been fully disclosed.
In addition, although Chinese officials vigorously promote "creating passages for fish" and sky-high price of conservation facilities, in the cold environment of high altitude, large drop and strong currents, traditional artificial fish passages have fatal blind spots that cannot be overcome. In this regard, experts pointed out that the Yarlung Zangbo Grand Canyon is a very special "fish dividing line". Even if a fishway is built, not all fish can pass through it smoothly.
According to a 2024 study on high-altitude fish passages in the Brahmaputra River system, after tracking five species of local fish, it was found that the efficiency of passing fish passages upstream was only 31.0%, and 61.7% downstream.
The Yaxia project has officially started, but the most critical document, the "complete environmental impact assessment", has not yet been seen by the outside world. According to reports, in August 2025, someone applied to China’s Ministry of Ecology and Environment for the disclosure of the Yaxia Project’s “Environmental Impact Report” and environmental impact assessment approval. The response received was that the relevant documents involved “state secrets” and would not be made public.
Experts point out that after the dam is built, a large amount of sediment will be trapped in the reservoir area, resulting in intensified downstream water flow, violent erosion of the river bed, and a cutoff of nutrients. The destruction of hydrology and sediment mechanisms will set off a chain reaction downstream. It will not only completely rewrite the fragile ecology of the Brahmaputra Grand Canyon section, but also seriously impact the agriculture and wetland environment of the downstream Indian plains and even the estuary delta.
Foreign media and environmental impact assessment experts have many questions about the Yaxia Project, but the most tense issue is actually hidden in China’s official construction start news. According to reports, Chinese officials solemnly announced the formal start of the lower reaches of the Brahmaputra River hydropower project. However, major official media at the time, including Xinhua News Agency, avoided discussing the most core project details in the start-of-construction announcement. They only mentioned in extremely general terms "five cascade power stations, straightening of bends, and water diversion through tunnels." It did not list the specific coordinates of the power station's dam site, dam height, reservoir capacity, and construction boundaries.
