I'm an Indian too, and I have been playing for almost one year. According to me these are the problems for hearthstone not being that famous in India:
1) Size: It's too big for a game to be in phones. Most of Indians play on phones. The size of the app is too big to even think of downloading. My friends refused to download the game just because of that.
2) Lag: the animation on phone lags alot, like alot alot. Even the match making animation lags like hell, sometimes you even miss your turn.
3) Online: hearthstone consumes alot of data. Which is quite expensive in India, yes I know Jio is there now but what will happen after 31st March? Back to square one.
4) Type of game: hearthstone is not a flashy fancy game, I myself used it on my phone first and then on my PC. It's hard to see that the game is good just by the screenshots of the game for a person who has never played such a game, people will obviously prefer FIFA NFS GTA or counter strike
I play in NA, max rank reached = 5, currently just fed up with the meta. Feel free to add me. :)