> so in 2150, or 2200, or someday, it will be a problem

No. Never of the magnitude you suggested. The population pyramid simply doesn’t have the shape required for a population bomb the likes of which we’re seeing in e.g. Korea.

Given current and projected fertility, it never blows out the way you suggest. It gently curves. If Indians, tomorrow, suddenly stop having kids that would be the problem you suggest. But they aren’t. And it isn’t.