Step aside, Three Gorges Dam. China’s latest colossal infrastructure project, if completed, will be the world’s largest hydroelectric plant, high on the Tibetan plateau on the border with India.

China says the Motuo hydroelectric plant it is building in Tibet is key to its efforts to meet clean energy goals. Beijing also sees infrastructure projects as a way to boost China’s sluggish economy and create jobs.

But the project has raised concerns among environmentalists and China’s neighbors — in part because Beijing has said so little about it.

The area where the dam is being built is prone to earthquakes. Tibet’s damming river, the Yarlung Tsangpo, flows into neighboring India as the Brahmaputra and into Bangladesh as the Jamuna, raising water security concerns in those countries.

What is known about the project?

China announced in late December that the government had approved construction of the Motuo project in the lower reaches of the Yarlung Tsangpo, but released few details about it. This includes the cost of the project, where the money will come from, which companies are involved and how many people are likely to be displaced.

What is known is that the dam will be in the Medog District of Tibet, in a steep canyon where the river makes a horseshoe bend known as the Great Bend and then drops about 6,500 feet over roughly 30 miles.

By harnessing the kinetic energy of that fall, the hydroelectric plant could generate 300 billion kilowatt-hours of energy per year, the state-run Power Construction Corporation of China, or PowerChina, estimates in 2020. That would be three times the capacity of the Three Gorges Dam, currently the largest in the world, the construction of which is China cost about 34 billion dollars.

China has not disclosed which company is building the dam, but some analysts say PowerChina, the country’s largest developer of hydropower infrastructure, is most likely involved. The company did not respond to requests for comment.

Experts say construction in Great Bend, a 500-meter-deep canyon with no roads, would likely take a decade because of technical challenges.

Even the basic design of the dam is unknown.

According to Fan Xiao, a senior engineer at the Sichuan Geology Bureau who spoke to The New York Times, one proposal, which he saw as a plausible approach, involved building a dam near the top of the Great Bend and diverting the water through huge tunnels drilled into the canyon.

China’s top leader, Xi Jinping, has promised that the country’s carbon emissions will peak around 2030 when coal is replaced by renewable energy sources. The ruling Communist Party, which uses major public works projects to demonstrate its engineering prowess, has for years studied ways to harness Yarlung Tsangpo’s power.

Are there environmental risks?

The same forces that created the Great Bend pose a risk to the dam that China is building on it. The Tibetan Plateau was formed by the collision of the Indian and Eurasian tectonic plates millions of years ago. Even today, the Indian plate is slowly moving towards the Eurasian plate, which is why the Himalayas are regularly hit by earthquakes.

Such seismic events threaten the safety of dams. Chinese officials said cracks appeared at five hydroelectric power stations in Tibet after that A magnitude 7.1 earthquake hit the city of Shigatse this month, killing more than 120 people.

Even if the Motuo Dam is built well enough to withstand an earthquake, it is difficult to contain the landslides and mudflows that result from an earthquake and can kill people living nearby. Experts say the massive excavations involved in building the dam could increase the likelihood of such disasters.

What about the people who live there?

It is difficult to know how the project was accepted by Tibetans and members of other, smaller ethnic groups living in the area. Tibet is tightly controlled by the Communist Party, which encouraged the Han Chinese to move to the plateau and strictly controls the practice of Tibetan Buddhism. Tibet is open to foreigners only with permission, and is usually off limits to foreign journalists.

In the past, Tibetans have held protests against hydroelectric dam projects that threatened to displace them, including protests last year in Sichuan Province, according to a newspaper report.

The Motuo Dam project is expected to bring more changes to Medog, which was once China’s most remote county. The government has built highways in the region that have attracted tourists and adventurers in recent years, says Matthew Akester, a Tibet researcher from India.

Now people will have to move to make way for the dam, which could require submerging farmland and towns. It is not clear how many people may be affected. Medog has 15,000 inhabitants.

Tibet, which is vast but sparsely populated, does not need much power, and the dam’s estimated capacity would also exceed what neighboring provinces require, Mr. A fan. Nearby Sichuan and Yunnan have many hydroelectric plants that produce more energy than the region needs. And sending electricity long distances to other parts of China would be expensive.

How are India and Bangladesh reacting?

The dam could affect people living downstream in the Indian states of Arunachal Pradesh and Assam, as well as in Bangladesh. If the dam traps sediment, it would make the soil along the river downstream less fertile and erode riverbanks and shorelines in India, he said. dr. Kalyan Rudra, professor of river science and chairman of the West Bengal Pollution Control Board, a government body.

Scientists in India and Bangladesh have asked China to share details of its plans so they can better assess the project’s risks. Indian diplomats have also urged Beijing to ensure that the project does not harm downstream states. China says it has taken measures to prevent negative consequences for its neighbors.

China’s secrecy breeds mistrust, said Genevieve Donnellon-May, a researcher at the UK-based Oxford Global Society who studies water policy and environmental conflicts. “Without Beijing releasing hydrological data and detailed plans for the dam, India and Bangladesh are left in the dark, making it harder to prepare to mitigate potential impacts,” she said.

Both China and India accuse each other of trying to establish control over water resources for strategic or economic gain – what some experts and officials call “hydro-hegemony”. The dam can be seen as a way of projecting Chinese power nearby disputed border with Indiaincluding Arunachal Pradesh, which China claims as its territory.

Being upstream, “China can make decisions that directly affect the flow of water downstream, raising fears in India,” Ms Donnellon-May said.

Some officials in India have proposed building a large dam on a tributary of the Brahmaputra to store water and prevent the reduction in flow that a dam in Tibet could cause. But dr. Rudra of the West Bengal Pollution Control Board said such a dam could cause the same problems with soil fertility and erosion.

Saif Hasnat contributed reporting. Do you contributed to the research.