The dollar fell against a basket of major currencies on Tuesday after China raised the official exchange rate of the yuan to its highest level in 30 months, boosting demand for other currencies.
The Bank of China set the official midpoint of the yuan at more than 6 per dollar before the market opened.
In overseas market trading, the yuan rose to more than 6 for the first time since June 2018.
The dollar index fell to around 90 and had fallen to more than 89 on Monday for the first time since April 2018.
The Australian dollar, a measure of risk appetite that tends to emulate the yuan, jumped to 77 US cents during trading in London, approaching its two-and-a-half-year high of more than 77 cents in the last days of 2020.
The dollar fell to around 103 yen and had fallen to around 103 on Monday for the first time since March.