As a sovereign country, we have no obligation to circulate their currency for foreign countries. Only the legal tender-RMB is allowed to circulate in China. After US dollars poured into China, the holders of US dollars had to convert them into RMB before they could use them. With the influx of dollars, banks in China have to pay the holders a corresponding amount of RMB when exchanging with banks in China, which leads to a large amount of RMB issuance, which in turn leads to inflation. Commercial banks resell the converted US dollars as foreign exchange reserves to the People's Bank of China. This is also one of the reasons why China's foreign exchange reserves remain high.