Does anyone know about the ATC in China? Flew to Chengdu and back (first time to China) and it was really funny that the Chinese ATC speak in Chinese to local a/c and you have to identify as "English" or "Callsign+FlightNumber+English".

Found it to be a safety hazard as well, when we had traffic northbound on the same flight level around 8miles away, which took us a while to notice, Thankfully the heavy noticed us before we caught onto him. Besides the FL check being in meters made things wonderfully confusing. Had a Polish F/o which made things even funnier.

I thought ICAO regulations meant that ATC all over the world use only English as their language of communication.

In my experience till date, this is the first time i've come across non-english chatter across the radios. Any other country that has the same policy?