The Mystery of India's Plummeting Covid-19 Cases

"Serological surveys — random testing for antibodies — show that a majority of people in certain areas of India may have already been exposed to the coronavirus, without developing symptoms...But many experts caution that herd immunity — a controversial term, they say — would only begin to be achieved if at least 60% to 80% of the population had antibodies."

So, you have multiple seroprevalence studies showing over 50% already exposed in crowded areas, and you have reason to think you need at least 60% to get herd immunity. Given that there have been multiple simulations that suggest it could be substantially less, it seems like covid-19 cases in India are probably going down for the classic reason that every pandemic ends, which is that it goes through a standard SIR curve (https://en.wikipedia.org/wiki/Compartmental_models_in_epidem...). I mean India's confirmed cases curve looks almost exactly like an SIR curve from a textbook. There's not a whole lot that needs explaining when something happens just about the exact way that, in 2019 and before, we would have said it would happen. We're just so freaked out in the middle of the pandemic that it is difficult for a reporter to just say that, apparently.