Amidst numerous rumours about the 'sweet water at Mumbai's Mahim creek, the Brihanmumbai Municipal Corporation said on Saturday that the phenomenon was not an unusual one. It also cautioned people that it would be dangerous to drink the water.

"We have taken samples of the water from various spots in the city, including the Mahim dargah. We have also taken an opinion from the National Institute of Oceanography in Goa [Images] and they have told us that this phenomena is not unusual. This can be caused by heavy rainfall and low tide," BMC commissioner Johnny Joseph told reporters.

"The Mahim creek is located in a semi-enclosed area where fresh water and sea water mix, especially during low tide, which caused the dilution. Also the Vihar lake on the outskirts of Mumbai has been overflowing for the past few days and has flown into the Mithi river, which could be the reason for the water tasting sweet," he said.

"All our analysis has shown that the water there is unpotable, and we appeal to people not to drink it. Also if any one has drunk that water and is experiencing vomiting and stomach problems, they should report to the nearest municipal hospital," Joseph said.

Tests conducted by the BMC's health department showed salt level in the sea water was as low as 600 particle per million, compared to the normal level of 10,000 ppm.

The NIO, at the request of the BMC, has nominated a senior scientist to analyse water samples and a report will be available in the next four days.

BMC will monitor water samples at fixed intervals, Joseph said.

Joseph said the National Environmental Engineering Research Institute had agreed to look into the matter and would take a fortnight to give its report.

The Maharashtra Pollution Control Board said the phenomenon could have been caused by an upsurge of groundwater.

Reports about sea water turning sweet also came in from the coastal area of Teethal in Gujarat's Valsad district, where numerous people considered the phenomenon a miracle and worshipped the water.

"The Arabian Sea water has turned a bit sweeter. Samples have been taken and sent to laboratories in Pune for testing," Valsad district development officer Indrish Vora, who tasted the "sweet" water, told PTI.