Mumbai’s tap water is the best among 21 major Indian metro cities, a study prepared by the Centre showed on Saturday. Delhi’s tap water was the worst and all 11 samples collected from the national Capital failed to comply with the Bureau of Indian Standards’ norms for drinking water.

Union Minister of Consumer Affairs, Food and Public Distribution Ram Vilas Paswan released the report on Saturday. “Tests were conducted on various parameters such as organoleptic and physical tests, chemical test, toxic substances and bacteriological tests in the first stage,” the ministry said in a statement.

The study showed that all 10 samples collected from Mumbai complied with the standards. But it was the only city as all other cities failed in at least one parameter. In Hyderabad, Bhubaneswar and Ranchi, one sample each failed to pass Indian standards. Of the 10 samples that were collected, five failed in Raipur, six in Amravati and nine in Shimla.

None of the samples drawn from 13 of the state capitals – Chandigarh, Thiruvananthapuram, Patna, Bhopal, Guwahati, Bengaluru, Gandhinagar, Lucknow, Jammu, Jaipur, Dehradun, Chennai and Kolkata – complied with the requirements. The Centre decided to study the quality of piped drinking water being supplied in the city in view of the objectives of the Prime Minister’s Jal Jeevan Mission.

“All should get clean drinking water and that is the objective of this activity,” Paswan said on Saturday while releasing the report, according to The Indian Express. “The objective is not to demotivate anyone, rather to encourage state governments to ensure quality potable tap water to all citizens.”

The Union minister added that the Centre wanted to make the norms mandatory for tap water. “Stringent action cannot be taken as the quality standards for piped water at present are not mandatory,” he said. “Once it becomes [mandatory], we can take action.”

“People should get pure water from the tap. There should be no water that causes diseases,” Paswan added, according to the All India Radio. “Have written to state governments and asked them to clarify the help they need.”

The ministry said that the first phase of testing included drawing water samples from Delhi, and the second included testing the tap water in 20 state capitals. “In the third phase, samples from capital cities of Northeastern states and Smart Cities identified by the Ministry of Housing and Urban Affairs have been drawn and are under tests,” the ministry said, adding that the results were expected by January 15. “In the fourth phase, it is proposed to test samples drawn from all the district headquarters of the country and their testing is planned to be completed by August 15, 2020.”