Here is the data from 2019 world population prospects. As you can see, India's population projections have only slowed down and declined successively from 2015 and 2017 and may be even slower for 2021...
Well, even Indian Muslims and Christians have a not so high fertility rate of 2.8-2.9.
Rest of India is already running near or below replacement. 2.0 to even 1.7.
That would require leveling of incomes of domestising of robots. ROK is an unequal society. South Korea has largest population poor old people. Since they can't earn.
Means a large portion of couples don't have kids. It would mean that once next generation grows pensioners will outnumber earners by a factor of multiple times.
That'd be a terrible economic collapse.