It’s been going on for a while since Xi took power and relations with the west soured. But it’s accelerated since the coronavirus pandemic. Some high-ranking CCP party members advocated and helped spread a conspiracy theory that westerners started covid-19 in China, if you can believe the audacity of that. Since then, the environment for westerners trying to live and work in China has gotten super toxic and uncomfortable. Press credentials for most western news agencies, including NY Times, have been revoked and they’ve been kicked out of the country as well.
Here’s some more info on it (and this was pre-covid, so things have only gotten worse since then).