Asian shares extended losses on Tuesday and European markets look set to follow after twin surveys showed China’s manufacturing sector in the grip of its worst slump in several years, raising fresh fears about the health of its economy. China’s official Purchasing Managers’ Index (PMI) fell to 49.7 in August from the previous month’s reading of 50.0, the weakest showing in three years. Separately, the private Caixin/Markit China Manufacturing Purchasing Managers’ Index (PMI) showed a final reading of 47.3 in August, the lowest since March 2009.