Power-coal prices continued to rise at Qinhuangdao Port during May Day holiday, with an average increase of 15 yuan per ton, Shanghai Securities News reported Tuesday.

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Prices reached their highest point in two and half years, according to the newspaper.

The price index averaged 808 yuan per ton –an increase of 9 yuan per ton from last month – and increased 5.35 percent in six weeks, according to the Bohai-Rim Steam Coal Price Index.

An industry insider said the price rise has lots to do with China's shrinking coal imports.