China's producer price index (PPI), a main gauge of inflation at the wholesale level, rose 6.6 percent in January year on year, the National Bureau of Statistics (NBS) announced Tuesday.

The January PPI was 0.9 percent up from the previous month, said a statement on the NBS website.

Climbing international commodities prices were keeping the PPI at a relatively high level, said Cai Xiao, an analyst with Hongyuan Securities.

In breakdown, the price of crude oil expanded 5.4 percent and that of raw coal went up 1.4 percent month on month.

China's PPI climbed 5.5 percent last year from the previous year.