In this Brookings Institution article about China, India is also discussed. It says, "India by contrast will keep growing quickly for a while. Its population is projected to approach 1.7 billion by 2060 before descending back to about 1.5 billion by century’s end." India is not at all in danger of extinction. Quite the opposite!

https://www.brookings.edu/articles/chinas-shrinking-population-and-constraints-on-its-future-power/