Of course it didn't go away. So you are saying that Western countries, that took all the Covid precautions, had an early second wave. However, a densely populated country that took very few precautions didn't have a second wave, but a deadly version months later? Do you have any references for the idea that India is suffering from a new variant of Covid?
For that matter, do we have any accurate information about the situation in India, except some choice photos in the media?
I think most of the pics, articles like this one are from Delhi. Which i think is in terrible shape. With cases not decreasing most hospitals would any way be stressed. But i assume it not terrible everywhere. My citie's Govt Hospital and Pvt ones are not over crowded or even anyway looks stressed as of now.
Do we have evidence that the virus has mutated into something more deadly? Such mutation is clearly not beneficial to the virus. My guess would be that the virus mutated into something with a higher R-0.
Read more about the optimal virulence here: https://en.wikipedia.org/wiki/Optimal_virulence
Optimal virulence is kinda bullshit with rapidly evolving things on small timescales...
Sure, if a mutation that makes it give deadly miocarditis 50% of the cases pops up, that strain would have a clear evolutionary disadvantage ...but if a strain that gives 2x worse pneumonia (and maybe a 2x death rate, that overall is still low) with 4x more coughing evolve, it will have an evolutionary advantage, more caughing => more virus in the air etc.
So you absolutely can have viruses evolving towards increased lethality, as long as people infected with the new strain spread the virus more and don't die too soon... you won't get to smth. evolving its way to 80% lethality, but it can very well evolve from <1% to ...50% (scary!).
The whole optimism about patterns of viral evolution is 100% wrong, unless you're thinking at very large timescales, and in environments where humans have not added so many accelerator factors!