It is impossible to have any level of herd immunity against a newly introduced virus. There may be a level of 'robustness' of the Indian immune response that enables them to mount a response more quickly. However there are time-delays built into the system that the response will still be measured in weeks.

Word on the street is this first wave of COVID-19 has lead to an approximately 10% exposure in populations as measured by either death or the formation of anti-COVID-19 antibodies. The other 90% of the still naive population will have to wait until stay-at-home restrictions are removed and we become social again and we get exposed. Or a vaccine is developed. The data seems to indicate that the presence of antibodies alone is not predictive of immunity which raises a question of the efficacy of a vaccine.

The relative isolation of the Indian population is a large factor in the low death rates seen. That, and as in most countries, the fidelity of the reporting is suspect.

India also uses a lot of Chloro-quinine.

I know way too many Punjabis to believe much of what they say, that they don't think makes them look good.