China's courier sector posted fast expansion in October, with a significant acceleration in business growth rate, according to an industry index released by the State Post Bureau on Wednesday.

The express delivery development index was 464.4 last month, an increase of 21.1 percent compared to the same period last year, according to the bureau.

China's express delivery volume remained high throughout October as the sector entered one of its busiest periods. On Oct. 22, the sector handled 729 million parcels, marking a 74 percent year-on-year increase and setting a new record for single-day business volume.

Express companies continued to enhance their cross-border service solutions in October, aiming to provide more convenient delivery services to consumers abroad, the bureau said.

The index is compiled based on data from major logistics firms operating delivery services. It reflects the overall business activities and trends in the country's courier sector.