Crude oil prices fell in Asia Monday after official data showed China’s manufacturing activity contracting for the second straight month in September, analysts said. New York’s main contract, light sweet crude for delivery in November, shed 56 cents to $91.63 a barrel and Brent North Sea crude for November retreated 40 cents to $111.99. Crude prices headed south after official data released by China showed manufacturing activity in the world’s largest energy consumer shrinking yet again, analysts said. China’s manufacturing purchasing managers’ index (PMI) was at 49.8 in September, up 0.6 from its August level but still below 50, indicating a contraction. “This morning we have official Chinese PMI data following HSBC’s survey at the weekend which supported its flash number revealing further contraction,” IG Markets said in a report.