Context: A draft of China’s new Five-Year Plan (2021-2025), which is set to be formally approved, has given the green light for the first dams to be built on the lower reaches of Yarlung Zangboriver, as the Brahmaputra is known in Tibet before it flows into India.
Issue

• China's plan to start construction of a controversial hydropower project is in the spotlight at a time Indian and Chinese troops have been pulling back at flashpoints in Ladakh as part of de-escalation after months of conflict.
• India fears that the Chinese project may disrupt downstream river flows, worsen water shortages and even cause flash floods. 
• The project was at a "preliminary planning and demonstration" stage.

Key Points

• China should aim to begin construction within the year on the giant hydropower project.
• The river Brahmaputra flows for about 2,900 km (1,800 miles) through Tibet, India and Bangladesh into the Bay of Bengal. 
• The "Yarlung Tsangbo (as the river is known in Tibet) downstream hydropower base" was listed in China's new five-year plan last week as one of the country's major energy development projects for the 2021-2025 period.
• China could build up to 60 gigawatts (GW) of generation capacity on the river, state media have reported, which would make it the world's biggest hydropower project, overtaking China's 22.5 GW Three Gorges Dam.
• China's five-year plan suggests that a number of long-pending proposals to build dams on the lower reaches, including near the border with India, may be approved.

India's key concern

• India is considering plans to build its own dam on the river to increase its water storage capacity and counteract the impact of the Chinese project.
• India has expressed concerns to China over the four planned dams on the upper and middle reaches, though Indian officials have said the dams are not likely to greatly impact the quantity of the Brahmaputra's flows in India because they are only storing water for power generation. 
• Also, they say, the Brahmaputra is not entirely dependent on upstream flows with an estimated 35% of its basin in India.
• Dams on the lower reaches and at the Great Bend are likely to raise concerns in India because of the location across the border from Arunachal Pradesh and the potential impact downstream.
• Diversion of the Brahmaputra is an idea China does not discuss in public, because it implies devastating India’s northeastern plains and Bangladesh, either with floods or reduced water flow.

Significance of Brahmaputra river for India

• The Brahmaputra flows for over 3,000km through Tibet, India and Bangladesh.
• It is crucial for India too as its basin is a critical water source for Arunachal Pradesh, Assam, Meghalaya, Sikkim, Nagaland and West Bengal.
• The Brahmaputra valley supports the lives of several indigenous communities.

Additional Information

About Brahmaputra river 

• Brahmaputra river system is one of the largest rivers in the world. In the Tibet region, it is known by the name of YarlungTsangpo.
• It enters by the names of Siang and Dihang in India. And after it is joined by its two main tributaries, the Dibang and theLohit, it is known by the name of Brahmaputra. It flows in Bangladesh by the name of Jumna. Finally, it merges with the Ganga river.
• The world’s largest riverine island, Majuli Island is on the Brahmaputra river in the state of Assam. Important cities along Brahmaputra are Dibrugarh, Pasighat, Neamati, Tezpur and Guwahati.
• Source of origin: The Brahmaputra river rises from Chemayundung glacier of the Kailash range near the Mansarovar Lake to the north of the Himalayas in the southwest Tibet region.
• Confluence of Mouth: The Brahmaputra drains into the Bay of Bengal before forming a huge delta along with the Ganga.

Course of the Brahmaputra river

• In Tibet, it runs parallel to the Himalayas for about 1,200 km. It turns into the south and creates a deep gorge through the Himalayas near NamchaBarwa and enters India under the name of the Dihang.
• Near Sadia, it receives the Dibang coming from the north and the Lohit coming from the east and enters the Assam valley where it is called the Brahmaputra. It flows in the west direction up to Dhubri and further below, it runs to the south and enters Bangladesh.
• The Brahmaputra receives numerous tributaries in the Assam valley. The number of streams joining the Brahmaputra on its right-bank is greater than that of those joining it on the left-bank. Most of the tributaries are large streams and they pour great quantities of water in the Brahmaputra.
• During the rainy season, it is 8 km broad, slow-moving and heavily laden with silt. Its channel is braided. It is notorious for floods and erosion of its banks. Recurrent floods not only hampers the navigation through the river but also the establishment of large towns on its banks.