Explained: Can China Really Stop The Flow Of Brahmaputra Water To India?

News18

2 days ago

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Taking technical, geographical and geopolitical factors into consideration, while China can alter the flow of Brahmaputra to some extent, it cannot fully stop it.
Assam Chief Minister Himanta Biswa Sarma has hit back at Pakistan for claiming China could choke the flow of the Brahmaputra to India with facts, stating that the river 'grows in India, not shrinks". His remarks came after a senior aide to Prime Minister Shehbaz Sharif, Rana Ihsaan Afzal, claimed that the suspension of Indus Waters Treaty with Pakistan could set a precedent for China to block the Brahmaputra River to India.
'If India does something like this, they stop the flow to Pakistan, then China can also do the same thing. But if things like this happen, then the entire world will be in a war," Afzal told Geo News.
But, can China really stop the flow of Brahmaputra river to India? Taking technical, geographical and geopolitical factors into consideration, while China can alter the flow of Brahmaputra to some extent, it cannot fully stop it. In fact, altering the flow, too, could have major implications.
Here's a closer look at why China cannot fully stop Brahmaputra's flow into India:
Partial Control Due To Geography
According to an article on natstrat.org, China accounts for only 22 to 30 per cent of the total Brahmaputra River Basin's discharge. The article has been authored by PK Saxena, former Indian Commissioner for Indus Waters and Adviser, Ken Betwa Link Project Authority, Bhopal, and Teerath Singh Mehra, former commissioner, Brahmaputra and Barak, Ministry of Jal Shakti, Government of India. The authors say that the Tibetan weather and scanty rainfall and snowfall amounting to 4-12 inches per annum are mainly responsible for this.
They also mention that Bhutan, despite its small size, contributes an equally significant 21 per cent while covering only 6.7 per cent of the river basin. Meanwhile, the Indian basin, which covers 34.2 per cent of the area, they say, contributes the maximum, 39 per cent, of the total discharge in the Brahmaputra River.
'Only 14 per cent of the entire Brahmaputra flow is therefore in the river before it enters India. The balance 86 per cent is contributed by the rains and monsoons in India. It is thus evident that China's contribution to the river flow of the Brahmaputra is minor, though not insignificant," the article says.
Assam CM Sarma, in his post on X, mentioned, 'China contributes only ~30–35% of the Brahmaputra's total flow — mostly through glacial melt and limited Tibetan rainfall. The remaining 65–70% is generated within India, thanks to: Torrential monsoon rainfall in Arunachal Pradesh, Assam, Nagaland, and Meghalaya, Major tributaries like Subansiri, Lohit, Kameng, Manas, Dhansiri, Jia-Bharali, Kopili and additional inflows from the Khasi, Garo, and Jaintia Hills via rivers such as Krishnai, Digaru, and Kulsi." 'At the Indo-China border (Tuting): Flow is ~2,000–3,000 m³/s. In Assam plains (e.g., Guwahati): Flow swells to 15,000–20,000 m³/s during monsoon," he added.
China's Dam Construction
China has approved the construction of the world's largest hydroelectric dam on the Brahmaputra (Yarlung Tsangpo in Tibet), which involves diverting part of the river's flow through tunnels to generate hydropower. While it poses concerns for India over China altering the flow of water, the concerns are seasonal (specially in non-monsoon months).
Assam CM Sarma had in January flagged concerns over China's proposed dam on the Brahmaputra in Tibet, saying the project will make the entire ecosystem fragile and dry. He also said the dam will make Assam depend on rainwater from Arunachal Pradesh and Bhutan. According to a PTI report, Sarma had also said the Government of India communicated its concern to the Chinese side. 'We have already communicated that if this dam comes then the Brahmaputra ecosystem will become fragile and dry and then we will depend on the rainwater from Arunachal Pradesh and Bhutan," he said.
However, the project poses challenges for China as well. According to a report in Hong Kong-based South China Morning Post, the Tibetan plateau is seismically active, making large dam projects risky with probabilities of big earthquakes. Any malfunction or natural disaster could cause catastrophic flooding downstream, which would be detrimental to China's own interests. The construction of the dam, hence, comes with its own engineering challenges.
According to a Business Today report, experts have warned that if the dam fails due to seismic activity, structural flaws, or sabotage, the impact could devastate Arunachal Pradesh and Assam 'in minutes". The construction of the dam also poses the risk of flooding of northeast Indian states with China controlling the flow of water downstream.
Meanwhile, India is also advancing the Siang Upper Multipurpose Project in Arunachal Pradesh, aiming to generate 11,000 MW of hydropower. The project is intended to bolster energy security and counterbalance China's upstream activities, but faces local opposition due to environmental and displacement concerns.
Geopolitical Implications Of Altering The Flow
China has not shared upstream hydrological data with India since 2022. Any unilateral action by China to manipulate the Brahmaputra river's flow could worsen India-China relations and complicate regional security dynamics. Not just India, any restriction to the flow could also harm China's diplomatic relations with Bangladesh, too, which will be impacted by any such alteration.
With such geographical limitations and geopolitical concerns, China cannot fully stop the Brahmaputra river flow into India. A large volume of the river is generated within India itself. While China's dam projects and control over the upper reaches give it some leverage, the river's strength downstream and regional geopolitical realities limit China's ability to 'weaponize the water".
First Published:
June 03, 2025, 14:36 IST
News explainers Explained: Can China Really Stop The Flow Of Brahmaputra Water To India?