BEIJING - China's coal prices continued to drop this week, a key price index showed.

The Bohai-Rim Steam-Coal Price Index, a gauge of coal prices in northern China's major ports, fell 0.5 percent from a week ago to 601 yuan ($87.22) per ton, according to Qinhuangdao Ocean Shipping Coal Trading Market Co Ltd.

It was the third straight week of price decline since the National Development and Reform Commission introduced measures to replenish coal supply as prices rose.