MUMBAI : The coronavirus cases doubled at a faster rate in Mumbai last week as compared to the previous week and the average growth rate of the viral infection also went up, according to the city civic body.On August 8, the country's financial capital recorded the slowest doubling rate of 89 days and the lowest growth rate of 0.79%.On Saturday, the rate of doubling became faster at 83 days and the average growth rate of COVID-19 cases rose to 0.84%.The average doubling rate in the city again slowed a bit on Sunday to 85 days and the growth rate decreased to 0.82%, as per figures of the Brihanmumbai Municipal Corporation (BMC).The city's D-ward, which includes areas like Peddar Road and Malabar Hill, had the fastest doubling rate of 50 days.