Which chess server is most stable in mainland China? I had been playing mostly on chess.com. Recently I moved to Shanghai, and chess.com is really unstable here. I had numerous abandoned games due to disconnection, and I can check that my internet is ok during the disconnection countdown. 

Maybe due to internet censorship? But surely a chess site can't be sensitive...

Could players in mainland China recommend a more reliable site please?
I suspect it is more about your Internet connection than which chess server you are connecting to.

I was watching the recent Nakamura-Duda quarter final in the speed chess championship, and Nakamura, who is known to have a great connection, was playing from a hotel somewhere but had connection issues, and lost a game. He continued virtually the whole match with no video feed due to this. The only thing that changed was his connection. Other Chinese players in the tournament have also had problems.

Many places are famous for their bad Internet, and that is the likely culprit, not the server you are connecting to.

That said, with a bad connection, the Internet Chess Club, and its predecessor, the Free Internet Chess Server, both use protocols that are require very little bandwidth to have a decent connection. I doubt there are any servers that require less as they are UNIX-based, and were started at a time when bandwidth was nothing compared to today.