Foreign exchange reserves must be placed in and managed by the central bank. Foreign exchange is dollars earned by export enterprises. Because it cannot be circulated in China, it is exchanged with the central bank. If the central bank changes RMB, it will not be printed without the State Council's approval. Therefore, China has the highest foreign exchange and inflation in the world. But the RMB is still exchanged at the exchange rate (this is not black), which is a debt of the central bank.