The clearance system of Things-to-Declare and Nothing-to-Declare channels (also known as the red and the green channels) is the clearance system generally adopted by the Customs of many countries for the baggage and articles carried by incoming and outgoing passengers. 

In China, the Customs Houses adopting this clearance system have set up the channels at sites for inspection and marked the Things-to-Declare Channel (Red Channel) and the Nothing-to-Declare Channel (Green Channel) in both Chinese and English. This customs-clearance system, aimed at simplifying customs formalities for passenger entry and exit, has currently been implemented by most of Customs Houses.