Crude oil prices declined in Asia Monday as weak economic reports from China and Japan dampened sentiment.

Light sweet crude for the November delivery declined 0.74 percent or 68 cents to $91.51 a barrel in electronic trading on the New York Mercantile Exchange during the Asian trading hours. Brent crude oil futures for the November delivery fell 0.60 percent or 67 cents to $111.72 a barrel on the ICE futures exchange in London.

Disappointing Chinese manufacturing reports sparked concern over growth slowdown in the world's second-largest oil consumer. The data released by the China Federation of Logistics and Purchasing showed that official Purchasing Managers' Index (PMI) gained to 49.8 in September from 49.2 in August, which was the lowest reading since November 2011. However, the index continued to remain in the phase of contraction for the second straight month since the reading is below 50 and also fell short of analysts’ estimate of 50.1 reading.

Meanwhile, the final reading of the HSBC Flash PMI, a measure of the nation-wide manufacturing, showed that manufacturing activity contracted for the eleventh straight month in September. The September PMI rose to 47.9 from a preliminary reading of 47.8 and the August reading of 47.6 but it still remains in contraction territory.

Adding to the downtrend, the Bank of Japan’s quarterly Tankan survey in September showed that business sentiment at large manufacturers declined to minus 3 from minus 1 in June. It has been negative for four straight quarters and indicating that the Japan, the world’s third largest oil consumer, continues to be affected by the weakening of exports following the soft global demand.

"Investors are focusing on demand indicators being weaker than expected. China's weak manufacturing activity, Japan's Tankan survey and social unrest in debt-hit Spain "point to downside pressure in the near term for oil prices,” Natalie Rampono, a commodity strategist with ANZ in Melbourne, told Reuters.

On Friday, light sweet crude for the November delivery gained 0.4 percent or 34 cents and settled at $92.19 a barrel on the New York Mercantile Exchange while Brent crude for the November delivery settled at $112.14 a barrel.