The NGT on Monday slammed Delhi Jal Board over rising ammonia levels in the Yamuna which has left its water beyond treatment, forcing the closure of Wazirabad and Chandrawal plants. “There is a report of increase in ammonia levels. What is your stand on it and what action have you taken in this regard,” a Bench headed by NGT Chairperson Justice Swatanter Kumar asked and asked the DJB to file a status report.