China has officially commenced construction of a massive $167.8 billion hydropower project on the Brahmaputra River in Tibet, near the Indian border in Arunachal Pradesh. The project, approved by Beijing in December 2023, is located in the Nyingchi region and was inaugurated on Saturday by Chinese Premier Li Qiang. This ambitious undertaking, which includes five hydropower stations, has raised concerns in India and Bangladesh, both of which rely heavily on the Brahmaputra for agriculture, drinking water, and ecosystem stability.

The dam is being constructed on the Yarlung Tsangpo River in southeastern Tibet, which becomes the Brahmaputra as it flows into India. Once completed, the hydropower stations are expected to generate over 300 billion kilowatt-hours of electricity annually, enough to power over 300 million people. This would make it the largest such effort on the planet, surpassing even China's Three Gorges Dam on the Yangtze River. The project is linked to China's carbon neutrality targets and economic goals in the Tibet region, with the electricity primarily transmitted to other regions while also meeting local power needs in Tibet.

India has expressed concerns to China regarding the potential environmental and strategic threats posed by the dam. These concerns relate to the downstream impact on millions of people in India and Bangladesh. New Delhi worries about potential disruptions to water flow, the blocking of nutrient-rich silt, and potential ecological damage. There are also fears that China could use control over the river as strategic leverage. Specifically, the Indian government is apprehensive that the dam could allow China to release large amounts of water during times of conflict, causing floods in downstream areas. Some Indian military officers have even described the project as a "water bomb" against India.

Arunachal Pradesh Chief Minister Pema Khandu has warned that the dam poses an existential threat to the people of the region and could be used as a "water bomb" by China. He emphasized that China is not a signatory to any international water-sharing treaty, which could have compelled it to follow global norms. Khandu stated that a sudden release of water from the dam could devastate the Siang belt, causing significant damage to property, land, and human life.

In response to these concerns, the Indian government has stated that it will monitor the situation and take necessary measures to protect its interests. India has urged China to ensure that the interests of downstream states are not harmed by activities in upstream areas. China's foreign ministry has maintained that the project would not have any negative impact on lower riparian countries and has promised to maintain communication with those countries.

Despite these assurances, concerns persist in India. Some experts believe that operating the dam to meet China's electricity needs will alter the river's seasonal flow. Reduced water flow in the dry season, coupled with sudden releases of water during monsoons, could intensify both water scarcity and flooding, endangering millions. Moreover, the project could impact sediment flows, as erosion in the region supplies a significant portion of the sediment that flows downstream on the Brahmaputra.

India is also developing its own hydropower project on the Brahmaputra in Arunachal Pradesh. The Siang Upper Multipurpose Project (SUMP) is intended to counter China's control upstream and generate electricity. However, this project has faced local opposition due to concerns about government secrecy and potential environmental impacts. Assam's Chief Minister, Himanta Biswa Sarma, has sought to allay fears, stating that the Brahmaputra is not dependent on a single water source and that the Union government is likely in discussion with China. He also noted conflicting scientific opinions on the dam's impact, with some believing it could reduce water flow and affect biodiversity, while others suggest it could cushion against floods.

The construction of this mega-dam highlights the complex water politics in the region and the need for continued dialogue and cooperation between China and India to ensure the sustainable management of the Brahmaputra River.