Could be testing. In general the advanced countries on SE Asia: Japan, China, South Korea, Singapore, Taiwan all seem to have been successful in stopping it.
You can be sceptical about the Chinese data but they couldn't keep Wuhan quiet and would not be able to keep an infection in Shanghai or Beijing quiet. It would be very obvious.
The only people you ever see with masks on in the UK, are Chinese, Koreans etc. Were they traumatised by SARs (much more deadly)? I don't know the reason why but these nationalities seem to be much more aware about disease in general. People say they wear masks to stop pollution but their people wear them in the UK, and we don't have a major pollution problem.