Mumbai's civic body has started the second phase of sero-surveillance study to assess the spread of COVID-19.<br />'' <br />''A serological survey involves testing of blood serum of individuals to check for the prevalence of antibodies against an infection.<br />'' <br />''The first phase of the survey, conducted last month had revealed a high proportion of asymptomatic COVID-19 infections in the city.<br />'' <br />''AIR correspondent reports, likely to be conducted over the next 12 days, the survey will cover three wards including Dadar, Matunga, Dharavi, Deonar, Govandi and Dahisar areas.<br />'' <br />''Additional Municipal Commissioner Suresh Kakani said the survey will throw light on prevalence of herd immunity and development of antibodies among the community members.<br />'' <br />''The survey has been jointly commissioned by the NITI Aayog, Municipal Corporation of Greater Mumbai and the Tata Institute of Fundamental Research.<br />'' <br />''Meanwhile, the pandemic has forced the state government to expedite setting up a boat ambulance service between Gateway of India in south Mumbai to Mandwa in Raigad district.<br />'' <br />''The service is likely to cut the traveling time between the two districts to thirty minutes as compared to three and a half hours by road.<br />'' <br />''<span style="color: #222222;">The service will benefit over a thousand villages in case of emergency where the patient needs medical attention in the golden hour.</span><span style="font-weight: bold;"> </span><br />