Delhi, at least, appears to have around a 5% detection rate over the past month. There was a population-wide serosurvey conducted from Aug 1st to 7th, which re

Delhi, at least, appears to have around a 5% detection rate over the past month. There was a population-wide serosurvey conducted from Aug 1st to 7th, which resulted in a 29.1% prevalence estimate, and an earlier one from June 27th to July 10th, which resulted in a 22.8% estimate. Assuming a 2 week period for IgG to be detected after infection, these surveys correspond to prevalence as of 20th July and 20th June roughly. With a population of 20M, that's around 1.25M new infections in that period. The confirmed cases by PCR testing increased by ~60000, yielding (roughly) a detection rate of 5%.