China's manufacturing activities posted a strong recovery in August, offering further signs that the world's second largest economy is emerging from the shadows of a protracted slowdown.

The purchasing managers' index (PMI) rose to 51.0 percent in August from 50.3 percent in July, marking the second monthly expansion in a row, and the highest reading this year, according to data jointly released by the China Federation of Logistics and Purchasing and National Bureau of Statistics (NBS) on September 1. A reading below 50 indicates contraction, while anything above signals expansion.

The 0.7-percentage-point monthly expansion also represents the biggest increase since January. In the months prior to August, the data had swayed back and forth.

Zhao Qinghe, a senior statistician with the NBS, said the figure shows the manufacturing activities have stronger growth impetus, and the economy is firming up in a more evident way.

China's non-manufacturing PMI fell to 53.9 percent in August from 54.1 percent for July, according to data released on September 3.