China's producer price index (PPI) slowed in May on declining oil prices, while living materials, a major constituent of PPI, expanded faster than the month before due to soaring food prices.

According to figures released yesterday by the National Bureau of Statistics (NBS), the factory-gate price rose 2.8 percent year-on-year in May after gaining 2.9 percent in April.

"The slowdown of the growth rate is mainly caused by the adjustment of oil prices," said Chen Jijun, a macroeconomic analyst from CITIC Securities. The producer prices of crude oil dropped by 3.9 percent in May.