Originating from the Angsi Glacier on the Chinese side of the Himalayas, the Yarlung Tsangpo River serves as a critical water source and transportation line for China, India and Bangladesh. Relatively unexploited for power generation in the past decade, the river has been increasingly at the center of diplomatic conflicts, since all three countries will face growing water shortages and skyrocketing demand for alternative sources of energy and power generation in the coming decades. Beijing's 2011-2015 energy sector blueprint calls for the installation of four hydroelectric dams along the river, including a 510-megawatt hydropower station at Zangmu that is already under construction. India is concerned that the construction of dams will reduce the water flow of the river, known as the Brahmaputra River in India. Beijing's plan to build three additional dams on the Yarlung River mainstream is certain to trigger objections from India, where the water descends into the plains of its northeastern state of Assam, whose agricultural production is vital to the region's economy and stability. In fact, facing its own power shortage, India has also identified the river as critical to its future power generation. But New Delhi's concern has another dimension: the historical dispute with China over the state of Arunachal Pradesh. Territorial disputes over Arunachal Pradesh have been an important factor in Sino-Indian relations since at least the drawing of the McMahon Line in 1914, but their scope, frequency and significance may be increasingly correlated with the water conflicts over the Yarlung River. Although there was a period of relative quiet after the Sino-Indian border war, Chinese territorial claims to "South Tibet" — the entirety of Arunachal Pradesh minus a small southeastern flank — have become more frequent and assertive as Beijing moves to consolidate its boundaries. The renewed tension over their shared water could add yet another dimension to the geopolitical competition between the two countries.