The Chinese government has tightened down on the traffic they allow into the country. Here are some general guidelines we can provide for better completion rates.
Suggested best practices
Use a wide list of originating numbers to call from.
Don't make more than 10 calls a day to the same country from a number.
Limit the calls per second to 1 CPS (Huge flag if faster.)
Spread out the duration of a campaign, or avoid huge campaigns, if possible, because China is very sensitive to them.
Every originating number needs to ring back to something like Voicemail.
NOTE: There is no guarantee China will end up allowing new calls to complete, or deny other calls under any predictable circumstances.