Mumbai: An alert of “very heavy" rainfall in Mumbai has been issued by the Indian Meteorological Department’s (IMD) regional centre in Mumbai on Tuesday, with the rains expected to intensify in the next 24 hours.

“There is low pressure formed over the Bay of Bengal and there is an outshore trough running from the Maharashtra coast to the coastline of Karnataka. This has strengthened the winds along the coastline and have further activated the monsoons," IMD, Mumbai director V.K. Rajeev told PTI.

The IMD expects “very heavy" rainfall in Mumbai and the Konkan region over the next 24 hours, he said.

“We expect that the rainfall in Mumbai will exceed 7 cms and will remain in a range of 7-14 cms. There are, however, a couple of areas in Thane district and the Konkan region which might witness showers upto 24 cms," Rajeev added. According to IMD records, in the 24-hour period till Tuesday from 8.30 am on Monday, Santa Cruz recorded 48.3 mm rainfall and Colaba had 26.6 mm.

Meanwhile, the Tulsi lake, one of the six major reservoirs from which Mumbai receives its water requirements, has started overflowing since Monday. It had begun overflowing last year from 12 July, a civic official said.

As of today, water in seven major lakes — which supply water to the city — is 4.99 lakh million litres (enough to last for about four months) compared to 11.48 lakh million litres last year, according to MCGM records.

The Municipal Corporation of Greater Mumbai (MCGM) had announced a 20% water cut earlier this month to cope up with water crisis arising due to “poor rainfall" in the city last month.

The civic body is expected to assess the latest situation of the availability of water on 31 July, and further action will be taken based on the assessment report, a municipal official had earlier said.