Travel Permit, also called Aliens' Travel Permit (A.T.P), is required to visit closed areas.It is issued by Foreign Affairs Section of the Local Public Security Bureau (PSB).The Law on the Control of Entry and Exit of Foreigners (Order of the President of the People's Republic of China (No.31), 22.11.1985, Chapter 4), says:

1   Article 20: Foreigners who hold valid visas or residence certificates may travel to places declared open to foreigners by the Chinese Government.
2   Article 21: Foreigners who desire to travel to places closed to foreigners shall apply for travel permits from local public security organs [i.e., the police].