Chandrawal and Wazirabad water treatment plants were forced to curtail production by 50 per cent due to high levels of pollution in the Yamuna, with ammonia levels rising to 1.2 ppm, against the permissible limit of 0.2 ppm.

According to the Delhi Jal Board (DJB), the release of untreated waste flows, mainly from industries through the Panipat drain into the Yamuna river, has been seen as the prime cause for the rise in pollution.