The Wire Staff 
New Delhi: China has green-lit the construction of what could be the world’s largest dam, with an estimated cost of at least $137 billion, on the Yarlung Zangbo River in Tibet which flows downstream as the Brahmaputra through India and Bangladesh.
State news agency Xinhua reported on December 25 that China has recently “approved the construction of a hydropower project in the lower reaches of the Yarlung Zangbo River.”
While the Xinhua report didn’t have further details, the South China Morning Post stated that the total investment in the dam could exceed 1 trillion yuan ($137 billion), making it the largest infrastructure project globally.
Chinese embassy spokesperson Yu Jin said on December 27 said that the project, “in lower reaches of Yarlung Zangbo River” aimed at low-carbon development. “It is also a safe project that prioritises ecological [protection], she added.
No further details were provided about the dam’s exact location or the type of hydropower project.
The Brahmaputra River, stretching 2,880 kilometres from China to India, has shaped the cultural and environmental landscapes in two Indian states of Arunachal Pradesh and Assam.
Run-of-the-river projects typically do not pose significant challenges for downstream countries, as they allow water to flow unimpeded. However, any initiatives to store or divert water could raise concerns by reducing the river’s flow further downstream.
A 2023 study cited by the SCMP, conducted by scientists from a Chinese university, argued that even hydropower projects could benefit the downstream riparian countries. The research from Tsinghua University’s department of hydraulic engineering suggested that reservoir storage could help maintain minimum water flow during the dry season, extending navigability in India by one to four months annually. The study also claimed that using reservoir storage to manage flood peaks could reduce flood-affected areas by up to 32.6% in India and 14.8% in Bangladesh.
According to Indian government records, Tibet has been the site of numerous hydropower projects over the past decade.
In July 2021, the Union Ministry of External Affairs informed the parliament that a hydropower project in Tibet was declared fully operational in October 2015. Subsequently, China planned three additional hydropower projects on the main stream of the Brahmaputra River in the Tibet Autonomous Region under its 12th Five-Year Plan (2011–2015). The first unit of one of these projects became operational in August 2020.
“Further, in March 2021, China adopted its 14th Five Year Plan which mentions plans for hydropower development on the lower reaches of the Brahmaputra river,” said MEA’s then junior minister V. Muraleedharan.
Regarding India’s stance on these developments, the minister stated that “as a lower riparian state, with considerable established user rights to the waters of the trans-border rivers, government have consistently conveyed our views and concerns to the Chinese authorities”.
“Government have urged them to ensure that the interests of downstream states are not harmed by any activities in upstream areas. The Chinese side has conveyed to us on several occasions that they are only undertaking run-of-the-river hydropower projects, which do not involve diversion of the waters of the Brahmaputra,” said the MEA in parliament.
In answer to another parliamentary question, the MEA said three years ago that the “government monitors all developments relating to the Brahmaputra river, including plans by China to develop hydropower projects”.
India and China had established an institutionalised expert-level mechanism to discuss trans-border rivers. However, these discussions were largely put on hold due to the military standoff in eastern Ladakh, which began in May 2020 and concluded earlier this month.
At the renewed meeting of the Special Representatives in Beijing last week, the agenda included the resumption of “data sharing on trans-border rivers”.