China's producer price index, which measures inflation at the wholesale level, fell 2.9 percent year-on-year in May, the National Bureau of Statistics announced on Sunday.

The figure marked a further drop of 0.6 percent from April's, according to data released by the NBS. For the January-May period, the PPI fell 2.1 percent.

The factory price of production materials dropped 3.8 percent, contributing 2.88 percentage points to May's PPI. Excluding the carryover effects from last year, new prices only contributed 0.8 percentage point to the general PPI of May, according to the NBS.

The decline of the PPI last month was in accordance with a three-percent drop of an index tracking the purchase price for industrial producers, according to the NBS.

The purchase price of ferrous metals fell 5.9 percent year on year in May, while that of fuel slumped 5.6 percent. The purchase price of non-ferrous metals and industrial chemicals fell 5 percent and 3.8 percent, respectively, according to the data.

The PPI data came along with a 2.1-percent rise in inflation in May, which eased 0.6 percent from April.