I can't imagine what 50+C feels like. The hottest I've endured was 41C. It's regularly 35+ with 80% humidity where I live and that's already uncomfortable enough.
I camp in the desert frequently, so I've got some experience with really high temperatures(not in the 50+ range, but in the upper 40s). It's not so bad if you take it really easy, but without a good supply of drinking water and shade you get problems fast.
Upper 40s would still be unbearable for me. I tolerate cold much better than heat - my body much prefers the cold. I think my ancestors were Scandinavian.
I was expecting the humidity in India to be pretty high, but 5 minutes of research suggests that it's only about 20% at midday. I've spend quite a bit of time in the desert during summer as well, and while upper 40s is no picnic, it's pretty manageable once you're acclimated.