BEIJING, June 1 -- China's manufacturing business activity continued improving in May, with an important index remaining in expansion territory, official data showed on Monday.

The manufacturing purchasing managers' index (PMI), a key measure of factory activity in China, posted at 50.2 in May, up from 50.1 in April, according to data compiled by the National Bureau of Statistics and the China Federation of Logistics and Purchasing.

A reading above 50 indicates expansion, while a reading below 50 represents contraction.