China has officially started construction of the world’s largest hydroelectric dam on the lower reaches of the Yarlung Tsangpo River in Tibet, about 50 kilometers from the Arunachal Pradesh border. The 60,000-megawatt Medog Hydropower Project has raised new concerns in India, prompting New Delhi to strengthen its strategic planning to address potential risks. In response, India is advancing the proposed 11,000-megawatt Siang Upper Multipurpose Project (SUMP) in Arunachal Pradesh, which would become the country’s largest hydropower facility once completed.

The SUMP project, led by state-run NHPC, aims to generate around 47 billion units of electricity annually at an estimated cost of 13 billion US dollars. However, while China’s Medog project is already under construction, India’s SUMP remains in the feasibility and preparatory stages. Experts warn that the massive upstream dam could alter the natural flow of the river, threatening agriculture, biodiversity, and local ecosystems, and increasing the risk of sudden floods.

India’s central government told Parliament it is closely monitoring China’s activities in the Brahmaputra basin and taking preventive and corrective measures to protect downstream communities. Efforts are also underway to strengthen flood forecasting, river monitoring, and infrastructure resilience in India’s northeast.