China's manufacturing activity slid further in August, with the purchasing managers index (PMI) standing at 49.2 percent, the lowest pace in nine months, according to the China Federation of Logistics and Purchasing (CFLP).

It marked the first time the index has fallen below 50 percent since December 2011. A reading of 50 percent demarcates expansion from contraction.

The falling PMI showed growth in the world's second largest economy remains in a downward movement, said Cai Jin, Vice Chairman of CFLP. The PMI reading in August retreated 0.9 percentage points from July.

"The [weak] external demand remains the biggest factor dragging down China's economic growth; meanwhile, domestic demand has not yet improved," said Fan Junlin, an economic researcher at the Agricultural Bank of China.

The PMI of China's non-manufacturing sector rose 0.7 percentage points to 56.3 percent in August.

"The rebound shows the non-manufacturing sector has played a more significant role in stabilizing economic growth," Cai said. "The recovery in the consumer service sector and dynamics of the information service industry have been building up a solid foundation for stabilized growth."