China boned itself so hard with the one child policy that they are either going to have to do a great leap forward, import a bunch of people under an immigration policy, or go to war. I suspect it will be the last one. They have way too many old people, too few young women, and a ton of guys (but still not as much as the older folks). It’s gonna cause a massive problem as they are well below replacement rate, there are few women, and a ton of their working class is gonna retire with nobody to support them in the next 20- 30 years or so.
Generally, immigration keeps a country stable, but they don’t really have much immigration.