A serological survey conducted between August and September in the national capital has found that nearly 33% of Delhi residents have developed Covid-19 antibodies. This essentially means that that 66-lakh people out of the two crore residents in Delhi may have been exposed to the virus and are now carrying antibodies. The figure rose from 29.1% in the second survey conducted in the first week of August. The first serological study found 23.4% people carrying antibodies. While 15,000 samples were collected for the second survey, over 21,000 samples were gathered in the first one.