New Delhi, Jan. 24 -- Authorities called off maintenance work on a key supply canal on Friday to restore normal water flow routes, officials said, after a spike in river pollution forced treatment plant shutdowns that have left large parts of the city without water for three consecutive days. The supply disruption, which has hit neighbourhoods in north, west and northwest Delhi, was triggered by high ammonia levels in the Yamuna river, which resulted from planned repair work on the Munak canal. Delhi Jal Board (DJB) officials said the crisis prompted an urgent decision to suspend maintenance and revert water flow to what is the regular channel. "A temporary maintenance-related diversion was undertaken on a section of the canal network, for which Delhi was requested to receive its water share through alternate channels. During this diversion, water flow from Khubru towards the Yamuna increased, leading to a sudden spike in ammonia levels, which affected raw water availability for treatment in Delhi and resulted in temporary water scarcity," said a DJB official said, asking not to be named. High ammonia loads prevent treatment plants from functioning effectively, forcing the temporary closure of the Wazirabad and Chandrawal facilities, which together supply around 200 million gallons per day (MGD). Officials said the situation is expected to stabilise by Saturday morning as ammonia levels recede and the Wazirabad plant resumes operations....