Water scarcity in Asia, exacerbated by climate change and rapid development, has become a major geopolitical concern, particularly for transboundary rivers.

For these shared waterways, control over upstream resources provides significant leverage, leading to heightened tensions and competition over a vital resource.

China's "Hydro-Hegemony" and its Neighbors

China's position as an upstream power on major rivers like the Mekong and the Brahmaputra gives it immense strategic advantage. Its dam-building projects, often undertaken without consultation with downstream nations, are the primary source of tension.

• Mekong River: China has built numerous dams on the upper Mekong (known as the Lancang in China) to generate hydropower and manage water flows. These dams are often blamed for intensifying droughts in downstream countries like Thailand, Cambodia, and Vietnam, which rely on the river for agriculture, fishing, and transportation. This gives China significant leverage over these Southeast Asian nations, forcing them to balance their need for Chinese investment with concerns about their water security.

• Brahmaputra River: China's ongoing dam projects on the Brahmaputra (known as the Yarlung Tsangpo in Tibet) have created a major flashpoint with India and Bangladesh. India is deeply concerned that China could potentially divert or withhold water, which is crucial for irrigation and drinking water for millions of people. China's refusal to sign international water treaties and its limited data-sharing with downstream countries have intensified a long-standing territorial dispute with India, making the river a key point of geopolitical friction.

South and Southeast Asian Responses

Downstream nations are managing these tensions through a combination of diplomatic engagement and a renewed focus on regional cooperation, though their options are limited.

• India's Defensive Measures: In response to China's upstream projects on the Brahmaputra, India has announced plans for its own hydropower projects, a move that signals a recognition of the need for defensive measures to secure its water supply. This bilateral tension over water resources is a new dimension to their already strained relationship.

• ASEAN's Dilemma: Southeast Asian countries are caught in a difficult position. While they are concerned about the Mekong's ecosystem and their water supply, they are also economically dependent on China. This has often led to a more cautious, diplomatic approach, as seen in the Mekong River Commission, which China is not a full member of. This lack of a binding, multilateral agreement makes it difficult for downstream nations to collectively challenge China's actions.

• Potential for Conflict: While water-related disputes have not yet led to armed conflict, they have become a major source of political friction. As climate change reduces water availability and population growth increases demand, the risk of a "water war" remains a serious concern for policymakers.