Chinese GDP is not a sum of locally reported GDPs. Locally reported GDPs have always exceeded the total GDP, sometimes by a large margin. Now they may lag.
A large motivation is how the taxes collected are shared between the central government and the local governments. A new tax sharing scheme introduced last year makes underreporting of the local GDPs profitable for the local governments, meaning they get to remit less taxes to the central government.
A large motivation is how the taxes collected are shared between the central government and the local governments. A new tax sharing scheme introduced last year makes underreporting of the local GDPs profitable for the local governments, meaning they get to remit less taxes to the central government.