Activity in China's manufacturing sector slowed markedly in August, twin surveys showed on Tuesday, the latest sign that the world's second largest economy is fast losing momentum.

The final Caixin/Markit manufacturing purchasing managers' index (PMI) slipped to 47.3 in August, the lowest reading since March 2009 and down from 47.8 in July. The reading, however, was a touch better than the flash reading of 47.1.