In a bid to tackle the spread ofcoronavirus in a more effective manner, the Brihanmumbai Municipal Corporation has put additional commissioners in charge of seven zones in the city.As per the order, seven additional commissioners will work towards improving the double rate of positive cases from 10 days to 20 days by May 17.These officials will be responsible for mapping positive cases, contact tracing, strict enforcement of norms in containment zones,door-to-door surveillance,identifying senior citizens with comorbid conditions and fever clinics, the circular dated May 7 said.They will also have to facilitate operations at private nursing homes, clinics, hospitals, ensure testing of symptomatic persons and creation of COVID care centres (CCC).Additional commissioners will have to personally visit their zones every day from morning till 2 pm, attend office post 3 pm and brief the municipal commissioner at 6 pm, the order stated.Of 19,063 COVID-19 cases in Maharashtra, 12,142 were reported in Mumbai and the city accounts for 462 deaths from the state's toll of 731.