The only way to do that (in any country where crypto stuff is restricted) is to do it in private. Now the problem is crypto currencies are highly saturated to small percentage of Indians, so this means it is rare to encounter a person who'll be holding some crypto, like say in a mall. There has to be a lot of Telegram group where individual swap crypto with INR/fiat. Just search on Telegram app itself (there's a search button in telegram that searches telegram groups). Or discord groups?
The only problem that you'll face to get those BTC or whatever is "T R U S T" Issues. Yes, if you trust someone then you won't get scam, if you cannot build trust, or trust never existed in the first place you'll get scammed and you won't have your crypto in return. To make yourself with it, you should spend some chatting time with the individuals, so you get to know them. Other way to know if a place is filled with trustable people with whom you can exchange with, is to see if there's a rep system in place. Like let's say if you exchange some BTC(I have) with USDT(you have), and our exchange is successful, I will give some point/rep and you will also give me some point/rep. This way whenever you do another exchange you will this public info visible to everyone that your previous exchanges were successful and thus you're trustable. If you're able to understand what I mean.