Today, the Brihanmumbai Municipal Corporation (BMC) said that Mumbai’s COVID-19 cases were increasing slower and would now double every 10 days. This is an improvement from 4 doubling days on March 24 and 6.3 on April 14

The BMC said this reduction in the rate of increase in cases is due to containment efforts, aggressive contact tracing and isolation.

Nationally, cases are doubling every 11 days compared to nine days for Maharashtra, as of April 27, our calculations show.

On April 12, 2020, Maharashtra changed its testing strategy and stopped testing asymptomatic contacts of confirmed COVID-19 patients, unless they were 34-weeks pregnant, on dialysis or chemotherapy, or health workers exposed to COVID-19 patients.

If fewer contacts of confirmed patients were being tested from April 12 onwards, it could have lowered the doubling days without an actual decrease in the spread of the disease in the city.

Between February 3 and April 15, Mumbai had tested 31,000 samples (2,374 per million)--more tests than any other city--as per the BMC’s update on April 16. The BMC has not released testing data since.

Mumbai has had 244 COVID deaths and 5,982 cases, as per the BMC’s 6 p.m. update on April 28. On April 29, the BMC said the city’s COVID-19 mortality rate was 3.7%, lower than the state average of 4.2%. The countrywide mortality rate is 3.2%.