"Drilling waste contained with chemical and oils from the ONGC's abandoned drilling site at Mandai (in Baramura Hill Ranges) was spilling over into Howrah river since Tuesday.
"Immediately we have shut four major water treatment plants and stopped supply of drinking water in the Agartala Municipal Corporation areas and its adjoining areas to prevent people drinking polluted water," Water and Sanitation Department Chief Engineer Bishu Debbarma told reporters.
He said that the engineers of the Water Supply Department and West district administration officials are testing the water at a regular interval and working round-the-clock to stop the spillover.
"We expect that the situation would be normal by tonight (Wednesday) or early tomorrow (Thursday).
We have also asked the ONGC to take suitable measures to prevent the spillover of drilling waste," Debbarma said.
The four major water treatment plants, that draw in supply from the Howrah river, cater drinking water to at least six lakh people in Agartala Municipal Corporation, adjoining Ranirbazar Municipal Council and Jirania Nagar Panchayat Areas.
Water Resources and Sanitation Minister Ratan Bhowmik, District Magistrate Milind Ramteke, engineers of various departments camping the affected areas and supervising the remedial works.
An Oil and Natural Gas Corporation (ONGC) spokesperson said that the company finished their drilling works at Mandai in Baramura Hill Ranges around a week ago and maintaining the standard scientific practice, did "effluent treatment" by finally covering the waste by high quality plastic sheets.
"To take away the waste substances, the local people cut off the plastic sheets leading to the spill over of drilling waste into the nearby Howrah river. Recent rain might have further worsened the situation," the spokesperson added.
Meanwhile, as the Howrah, like other Tripura rivers, flows into Bangladesh, officials of Assistant High Commission of Bangladesh here informed their government of the development and are monitoring the situation.
"We have informed about the spillover of chemicals and oils into the Howrah River to the Water Resources Department in Dhaka to take suitable steps," said Assistant High Commissioner Mohammad Shakhawat Hossain.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)