Re: China's population (up thread), it's due a hard landing as they have a 4:2:1 population model thanks to the one-child family policy on top of a shocking sex imbalance. Up to thirty million girls are "missing" compared to what you would expect from a normal demographic ratio, so that's thirty million young men struggling to find a bride in a society where marriage is still considered necessary to start a family.
On top of that, there is a rumour going about (especially after Covid-19 data problems), that authorities have been inflating the birthrate, partly to look good and partly to massage central Government contributions. The shit is hitting the fan now, as those missing children are not appearing in schools or nurseries. South China post have reported up to half may close this year, in a lot of the regional cities.
So yes, China is looking at a hard demographic landing and it's coming in sooner then anyone thought it would happen. The flip side is that they will still "only" have half a billion people left at the end of the century and Xi has a handy surplus of men now, if he wants to do something provocative such take Taiwan.
China, as a great power, isn't going anywhere, but it may be tempted to take some risky bets whilst they still have a demographic dividend.
India's been quiet so far. They are the one to watch in the future as they have not really asserted themselves on the political stage in the same way and they are now the largest populace in the world.