GUWAHATI/NEW DELHI: Assam CM Himanta Biswa Sarma Monday demolished latest Pakistani scaremongering after India decisively stepped away from Indus Waters Treaty – what if China cuts off Brahmaputra’s water supply to India? He called it a myth & cited hard data to prove the river slicing through Assam is a rain-fed watercourse that grows in India, not shrinks.“Let’s dismantle this myth – not with fear, but with facts and national clarity,” Sarma posted on X, adding: “Brahmaputra is not a river India depends on upstream – it is a rain-fed Indian river system, strengthened after entering Indian territory.”According to Sarma, China’s contribution to the river’s flow is minimal, only 30-35%, mostly from glacial melt and limited Tibetan rainfall. The rest 65-70% is generated inside India by torrential monsoon rainfall across Arunachal, Assam, Nagaland, and Meghalaya.Sarma further listed major Indian tributaries feeding Brahmaputra – Subansiri, Lohit, Kameng, Manas, Dhansiri, Jia-Bharali, and Kopili, along with inflows from Khasi, Garo, and Jaintia Hills via rivers like Krishnai, Digaru, and Kulsi.If China ever does “turn off the tap”, Sarma said it might actually reduce flood devastation in Assam, which displaces lakhs annually. At Tuting on India-China border in Arunachal’s Upper Siang district, Brahmaputra’s flow is 2,000-3,000 cubic metre per second – but swells to 15,000-20,000 cubic metre per second in Assam during monsoon.Backed by water governance experts, Sarma’s post drew strong support from Nilanjan Ghosh, vice-president of Development Studies and senior director at Observer Research Foundation in Kolkata. Ghosh said China’s upstream interventions will have “negligible or almost no effect” on Brahmaputra’s overall flow.Brahmaputra originates at Angsi Glacier in Tibet, flows 1,625km as Yarlung Tsangpo before entering India where it runs 918km – as Siang, Dihang, then Brahmaputra – and finishes its 2,880km journey with a 337km stretch in Bangladesh, before meeting Ganga. Though China has announced plans to build a massive hydropower dam on Yarlung Tsangpo, Indian experts said Brahmaputra’s scale and Indian monsoon strength make fears of water cuts largely unfounded.IDSA senior fellow Uttam Sinha, citing peer-reviewed data, said even during lean periods Yarlung Tsangpo’s annual outflow from China is far lower than Brahmaputra’s total discharge in India.