Three patients of BA.4 and one of BA.5 Omicron sub-variants of coronavirus have been found in Mumbai and all of them have already recovered from the infection, the Maharashtra health department said on Monday.

BA.4 and BA.5 are sub-variants of the highly transmissible Omicron strain of the coronavirus which had triggered the third wave of the pandemic in the country.

The health department said a report of civic-run Kasturba Hospital's laboratory confirmed the presence of BA.4 sub-lineage in three patients and BA.5 sub-variant in one patient in the metropolis.

Out of the four patients, two were girls aged 11 and two men in the 40 to 60 age group, it said.

"All these patients have recovered under home isolation," the department stated.

Mumbai on Monday reported 1,118 new COVID-19 cases, about 38 per cent less than the previous day, while no fresh death due to the infection was registered in the metropolis even as the active tally shot up to 11,331, the local civic body said.

With this, the city's tally of COVID-19 cases increased to 10,81,865, while the death toll remained constant at 19,573, said a Brihanmumbai Municipal Corporation (BMC) bulletin.

Mumbai has logged four-digit coronavirus infections for the seventh day in a row though it reported 685 fewer COVID-19 cases in the last 24 hours compared to 1,803 infections on Sunday which also saw two fatalities linked to the infection.

According to the bulletin, 676 patients recovered from the respiratory illness in the last 24 hours, pushing up their cumulative number to 10,50,961.

Mumbai's active tally climbed to 11,331 and growth rate of the infection stood at 0.144 per cent between June 6 and 12, the BMC said.

Notably, the case doubling rate of coronavirus infections in the financial capital dipped below the 500-day mark at 475 days from 513 days on Sunday.

The positivity rate, or cases detected per 100 tests, stood at 11.61 per cent.

The metropolis generally logs less number of COVID-19 cases on Mondays, as compared to other days, due a dip in number of tests during the weekend.

As per the bulletin, 9,622 COVID-19 tests, the lowest since June 6, were carried out in the metropolis, taking their overall tally to 1,72,99,943.

On Sunday, 15,922 swab samples were tested in the city.

Out of the 1,118 new cases, 1,046 were asymptomatic and 72 symptomatic patients were admitted to hospitals and of them, six were put on oxygen support, the BMC said.

The bulletin said out of 24,877 hospital beds earmarked for coronavirus patients in the city, only 478 beds are currently occupied.

The metropolis, however, remains free of sealed buildings and containment zones.