I read through the tweets but didn't see any mention of the fact that many parts of India might already be at localized herd immunity already. e.g. https://www.bbc.com/news/world-asia-india-53576653

At the high level, there are two reasons for the steep drop in Coronavirus in India:

1. Localized herd immunity in the cities. Link above points to results from Mumbai. Recent studies from Delhi have also shown similar numbers (>50% of population with antibodies).

2. Low testing in rural areas. It's hypothesized that a lot of the current spreading of the virus is happening silently in rural area, where testing infrastructure is underdeveloped.