The People’s Bank of China (PBOC) set the USD/CNY reference rate at 6.3735 on Wednesday while comparing to the previous fix and the previous close at 6.3728 and 6.3687 respectively. It's worth noting that market expectations backed 6.3720 as a quote before today's fix published.
"With 10 billion yuan worth of reverse repos maturing on Wednesday, china central bank injects 190 billion on a net basis on the day," said Reuters following the release.