Chongqing hukou used to have a Chongqing license plate, but now Chengdu hukou can't use the previous Chongqing license plate. According to Article 43 of the Regulations on Motor Vehicle Registration, the owner or manager of a motor vehicle shall register the motor vehicle at the motor vehicle management office where the owner or manager is registered, and the motor vehicle number plate shall be made and managed according to the regulations of the location where the owner or manager is registered. Therefore, if your household registration has been moved to Chengdu, it is necessary to move the registration place of the vehicle to Chengdu and reissue the Chengdu license plate. If you still use Chongqing license plate, you may be considered illegal by traffic police, fined or detained.