Many of Asia’s great rivers rise on the Tibetan Plateau in Chinese territory before flowing into neighbouring countries. This gives China a natural geographical upstream advantage over how much water flows to the countries below, and when. Yet it has refused to accept common rules for sharing that water. China’s interest in these rivers goes beyond hydropower. It has been using rivers rising in its territory as strategic levers to influence policies and politics of downstream countries.
In 1997, it was one of only three countries, along with Burundi and Turkey, to vote against the UN Watercourses Convention, the only worldwide treaty on shared rivers. The convention requires countries to use shared rivers fairly, avoid causing serious harm to neighbours, share data and give advance notice of major projects. China argued that the convention did not respect its sovereignty over rivers within its territory and was unfair to upstream countries.
South China has plenty of water, while its north and north-west face severe shortages. Its answer is the South-to-North Water Diversion Project, the world’s largest water transfer scheme. According to Chinese government documents, the Eastern Route, operating since 2013, carries Yangtze river water from Yangzhou along the Grand Canal. The Middle Route, opened in 2014, carries water from the Danjiangkou Reservoir on the Han River north to Beijing. According to Chinese media, by August 2026 the two routes together had moved more than 90 billion cubic metres (BCM) of water to 48 cities and 195 million people.
This came at a cost. According to newspaper reports, the project displaced at least 330,000 people, and the depleted Han River now needs the Yinjiangbuhan Tunnel to carry Yangtze water back into it. If China is willing to uproot its own people and strain its own rivers to meet the needs of the north, there is little reason to expect restraint where its rivers flow into other countries.
The proposed Western Route, also known as the “Red Flag River” project, would extend this approach to international rivers. According to news reports, it aims to divert about 44.8 BCM of water a year from rivers on the Tibetan Plateau, including the Yarlung Tsangpo (Siang), the Mekong and the Salween, to dry regions such as Xinjiang. In 2003, news reports first revealed a plan to divert about 40 billion cubic metres a year from the Yarlung Tsangpo. In May 2021, President Xi Jinping personally chaired a major high-level symposium in Henan province to aggressively accelerate and advance the next phases of this massive infrastructure project.
Meanwhile, China approved the Medog dam on the Yarlung Tsangpo in December 2024 and began construction on 19 July 2025. The dam will store about 5.5 BCM of water. The Government of India estimates that China may divert around 40 BCM of water through the Red Flag River Project and the Medog dam from the Siang river, prior to its entry into India through Arunachal Pradesh.
The Mekong: a river held back
The question we must ask ourselves if water diversion from the Siang is a one-off Chinese attempt to divert water towards its arid north and north-western provinces, or part of a strategic design to weaponize transboundary rivers. Consider the case of the Mekong river.The Mekong runs about 4,350 km through China (where it is called the Lancang), Myanmar, Laos, Thailand, Cambodia and Vietnam. Nearly 200 million people depend on it, mostly through farming and fishing. China built its first dam on the upper Mekong in the 1990s and now operates a total of 11 dams.
China’s part of the basin had normal to high rainfall and snowmelt in 2019. Yet its dams held back more water than ever while the countries downstream suffered a severe drought. The researchers found that river levels along the Thai–Lao border would have been much higher without the dams.
The lack of warning is equally serious. According to newspaper reports, on 31 December 2020 the Jinghong dam suddenly cut its outflow, and the river fell by about one metre at Chiang Saen in Thailand, 380 km downstream. China informed downstream countries only six days later. In August 2024, flash floods and mudslides in 10 Thai provinces killed 22 people and forced nearly 45,000 from their homes. A former Thai Prime Minister suggested that the high Mekong levels could have come from water released by Chinese dams; China denied this. Either way, downstream countries know little about these releases and have no control over them.
Kazakhstan: the Ili and the Irtysh
Two major rivers, the Ili and the Irtysh, flow from Xinjiang into Kazakhstan, and China uses up to half the water in each. For decades Kazakhstan has failed to get binding limits on how much water China utilizes upstream.According to newspaper reports, in the summer of 2023 the Irtysh fell to its lowest level since at least the 1990s. Kazakh officials and experts said the main cause was China’s growing use of the river’s water.
China takes more water for farming and other needs and has built several dams on the upper part of the river. Officials of Kazakhstan’s Water Resources Committee said China had cut the flow in the Irtysh basin by 21.5%, or about 2.1 BCM. They also said China had cut the flow into the Balkhash–Alakol basin, which includes the Ili, by 15.3%, or about 2.3 BCM. The Ili feeds Lake Balkhash, and Kazakhs fear the lake could go the way of the Aral Sea.
According to newspaper reports, the worst effects of the 2023 low water of Irtysh river were also felt in Russian region, disrupting barge traffic and hurting river transport and fisheries. Russian officials blamed Kazakhstan for sending too little water. This shows how a shortage that starts in China spreads downstream river and causes friction between countries that had no part in creating it.
Floods from across the border
India and Nepal have both suffered disasters that began in Tibet. On 11 June 2000, a dam on the Yigong River, a tributary of the Yarlung Tsangpo, suddenly burst as a result of a landslide. The Siang rose to its highest recorded flood level at Pasighat of 167.54 metre, well above the danger level of 153.96 metre. The flood washed away strategic bridges, killed 30 people, left more than 100 missing and displaced over 50,000 people.
On 26 August 2026, a glacier collapse and an avalanche of ice and rock near Langtang Lirung, close to the Nepal–China border, sent a flash flood down the Bhote Koshi from Tibet into Nepal. It struck without warning and destroyed the Gyirong border crossing. According to a news report of 22 October 2026, more than 1,500 people had died and 5,600 were still missing. At least 10 Districts in Bihar were saved from flood damage due to the 57 year old Kosi Barrage.
What this means for the Siang
In the mid-1990s, Ismail Serageldin, then the World Bank’s Vice President for Environmentally and Socially Sustainable Development, declared: “If the wars of this [20th] century were fought over oil, the wars of the next century will be fought over water.”
The rivers flowing out of Tibet show the pattern. Water is held back in dry months, released without warning in wet months, and diverted for China’s own needs, while downstream concerns are ignored. The Siang is even more exposed. According to a Central Water Commission report, about 65% of its yearly flow, and 84% of its winter flow, comes from China. Any large-scale diversion upstream would therefore be felt most sharply in winter, when farming, fishing and drinking water supplies in the Siang valley and in Assam depend on a steady flow.
The wet season carries the opposite risk. A sudden release, or a failure at a dam built on an active fault, could send a flood down the valley with little or no warning. China’s own scientists say the river is becoming more prone to floods.
China’s neighbours have learned that assurances alone do not guarantee timely warnings or a fair share of water. Kazakhstan has watched its rivers and lakes shrink while staying largely silent to avoid harming wider ties with China. That silence reflects China’s aggressive “wolf warrior” diplomacy and economic pressure, which signal that countries challenging it pay a price. Once China controls the source of a river, the flow of water can become one more instrument of pressure and coercion.
India has no binding protection against these risks. There is no water-sharing treaty with China, and the agreement for sharing Brahmaputra flood data expired in June 2023. China has also rejected the global convention that would require it to inform or consult its neighbours and not provided any information regarding the Medog dam with India, despite multiple requests by the Ministry of External Affairs.
India must therefore protect herself. Experience of other countries such as Thailand, Laos and Kazakhstan suggest that ignoring Chinese activities upstream would be naïve to the point of foolishness. The Siang Upper Multipurpose Project, with a proposed storage of about 9.2 BCM, could absorb sudden releases upstream and sustain the river’s flow in the lean season. Declared a National Project by the Government of India in 2008, it would give India a safeguard that does not depend on China’s goodwill. The first step is the Pre-Feasibility Report: a scientific study of whether such a protective project is possible, carried out with the full involvement of the people of Siang.
(This is the second part of a series of articles regarding the Siang Upper Multipurpose Project. This article has been jointly authored by Er. Atop Lego, retired Chief Engineer PWD, Er. Gobo Erang, Chief Engineer PWD, Er. Atek Miyu, retired Chief Engineer HPD, Er. Ado Burang Chief Engineer PWD, Er. Getom Borang Chief Engineer, WRD, Er. Karom Perme Chief Engineer, HPD and Er. Aken Jongkey, Superintending Engineer, PWD. Views expressed are personal).
