The Assam government has sent water samples of the Brahmaputra to the Hyderabad-based Indian Institute of Chemical Technology after reports that the river’s water has turned blackish because of suspected Chinese activities upstream in Tibet. Samples were collected from several points of the 891km river from Sadiya in eastern Assam to Dhubri in the west bordering Bangladesh, chief minister Sarbananda Sonowal said on Saturday. The Brahmaputra is formed after three rivers — Lohit, Dibang and Siang, all flowing through Arunachal Pradesh — meet near Sadiya. The Siang originates in Tibet, where the river is called Yarlung Tsangpo. Blackened, muddy waters of the Siang triggered conspiracy theories about China constructing a tunnel to divert the water of Yarlung Tsangpo to the parched Xinjiang province. Beijing denied the reports or any plan to contaminate the Siang and Brahmaputra. Indian officials attributed the blackening of water of the two rivers to a major earthquake in Tibet. “The Hyderabad institute and the Indian Institute of Technology in Guwahati have been asked to test the water samples and find out the reasons behind the water turning black. Remedial action would be taken after finding out the reason,” Sonowal said.
Ninong Ering, the Congress MP representing Arunachal East, sounded the alarm in November, saying the Siang’s water has turned unusually turbid and is threatening aquatic life. The turbidity, he said, was caused by a cement-like substance possibly flushed down from Tibet. Ering wrote to Prime Minister Narendra Modi, highlighting the issue. Days later, the frontier state’s public health engineering department tested samples from near Pasighat town and found the nephelometric turbidity unit (NTU) to be 425, abnormally more than the permissible limit of five.
Assam was late to react, but water resources minister Keshab Mahanta said Siang’s problem flowed into the Brahmaputra after tests at three places — two in Dibrugarh and one in Sonitpur districts — revealed an NTU level of 295, 404 and 162 respectively. “We have taken up the matter with the water resources and other central ministries,” Mahanta said.