Defence Minister Rajnath Singh on Tuesday said that New Delhi is on alert regarding China’s plan to build a dam on the Brahmaputra river in Tibet close to the border with India.

“The Indian government is on alert,” Singh said at an event in Agra when asked about the Chinese project.

On December 25, Chinese state-owned news agency Xinhua reported that Beijing had approved the construction of a hydropower project in the lower reaches of the Yarlung Tsangpo, which is the Tibetan name of the Brahmaputra.

First announced in 2020, it is touted to be the world’s most expensive infrastructure project with a cost of $137 billion. It is unclear when the project’s construction is due to begin.

The dam is to be built at a gorge in the Himalayan reaches where the Brahmaputra makes a U-turn to flow into Arunachal Pradesh, Assam and then into Bangladesh, The Indian Express reported.

However, concerns have been raised in India and Bangladesh about the project. Critics say that the dam could potentially alter local ecologies and change the flow and course of the river, affecting millions living in the agricultural plains downstream.

The dam could also enable Beijing to release vast amounts of water and flood border areas during times of conflict, PTI reported.

On Friday, Ministry of External Affairs Spokesperson Randhir Jaiswal said that the Indian government had consistently raised concerns with Beijing about the project.

“As a lower riparian state with established user rights to the waters of the river, we have consistently expressed, through expert level as well as diplomatic channels, our views and concerns to the Chinese side over mega projects on rivers in their territory,” Jaiswal said.

“These have been reiterated along with the need for transparency and consultation with downstream countries following the latest report,” he added. “The Chinese side has been urged to ensure that the interests of downstream states of the Brahmaputra are not harmed by activities in upstream areas.”

New Delhi would continue to monitor and take necessary measures to protect its interests, said Jaiswal.

On Monday, the Chinese government said that the decision to construct the dam was made “after rigorous scientific evaluation”. The project will not hurt ecological conditions and the rights and interests related to water resources of India and Bangladesh, said Chinese Foreign Ministry Spokesperson Guo Jiakun.

This came weeks after Indian National Security Adviser Ajit Doval and Chinese Foreign Minister Wang Yi met in Beijing, in what was the first meeting of the special representatives of the two countries in five years.

Following the December 18 meeting, the external affairs ministry had said that Doval and Yi provided “positive directions” for the resumption of border trade, the Kailash Mansarovar Yatra and data sharing on trans-border rivers.