Two historic milestones will be reached in 2023. For the first time in many centuries, India’s population will exceed that of China. In addition, China’s population will begin declining in 2023. During the latter part of this century, India’s working age population will likely be at least twice as large as China’s. By that time, India will likely have the world’s largest economy, with the US falling back to number three.
The Economist produced a useful graphical presentation of this historic moment:

Of course, there could be surprises ahead. But in recent years, the demographic surprises in East Asia have been to the downside, with birthrates falling much faster than expected.