New Delhi, July 22 -- India is keeping a close watch on China's construction of what is set to be the world's largest hydropower dam on the upper reaches of the Brahmaputra river and could fast-track a multipurpose dam in Arunachal Pradesh to act as a buffer against sudden changes in water flows, people familiar with the matter said on Monday. Chinese Premier Li Qiang presided over a ceremony on Saturday marking the start of construction on the $167-billion dam on Yarlung Tsangpo river in Tibet, according to reports in China's state-run media. The Motuo hydropower station is set to overtake the Three Gorges dam as the world's largest. There was no reaction from Indian officials to the development, though people familiar with the matter said on condition of anonymity that New Delhi had conveyed its concerns over the project to Beijing through diplomatic channels. The project has drawn criticism for its potential impact on the environment of Tibet and on millions of people in India and Bangladesh. Concerns about the dam could spur India to fast-track a multipurpose dam in Arunachal Pradesh, known as the Siang Upper multipurpose storage project, to act as a buffer against sudden changes in the flows of the Siang and Brahmaputra rivers, the people said. The Chinese dam is located around a "great bend" on the Yarlung Tsangpo river, which is known in India as the Brahmaputra. The Siang, which flows through Arunachal Pradesh, is the Brahmaputra's main tributary that connects it to the Yarlung Tsangpo. In June 2022, the government entrusted the National Hydroelectric Power Corporation Ltd, India's largest state-backed power firm, with preparing a preliminary feasibility report and a detailed project report for the proposed Upper Siang dam. While there was no official reaction to the start of construction of the dam in Tibet, the people pointed to the position taken by the external affairs ministry on the matter during a media briefing on January 3....