New Delhi, Dec. 17 -- A Yamuna activist on Tuesday wrote to lieutenant governor VK Saxena and Delhi chief minister Rekha Gupta, flagging excessive usage of defoamers in the Yamuna for a prolonged period, and highlighting possible adverse affects it may have on the river ecology and aquatic life. In a letter, activist Pankaj Kumar wrote that defoamers were used only for a brief period around Chhath Puja over the past few years, but this year, their usage has continued since October 15. "This year, the activity began in the second week of October and continued unabated for over 60 days as of December 15, with plans to extend it for additional months. Personal observations confirm that defoamer is being sprayed in large quantities even when no...