BEIJING: China's coal imports jumped 21.4% in July from a month earlier to 32.89 million tonnes, customs data showed, boosted by strong demand for electricity as households and businesses cranked up their air conditioning in the face of hot weather.

China, the world's biggest coal user, took in a total 187.36 million tonnes of the fuel in the first seven months of 2019, up 7% from the same period last year, data from the General Administration of Customs showed on Thursday.

The State Grid also recorded the highest ever power transmission loads last month in 10 provinces, including the industrial heartlands of Shandong, Jiangsu and Zhejiang.

The climb in imports came even as customs halted coal clearances at several ports, from Dalian in the north to Fangchenggang in the south, without giving any explanation.

Traders said that some inland ports in Inner Mongolia also tightened coal imports by reducing the number of trucks that could enter at border checkpoints.

The traders and other market participants said they do not expect the restrictions to be lifted in the short-term as China has already imported large volumes of coal this year and as domestic mine output has been rising.

The central government has been urging domestic coal miners to ramp up production to ensure sufficient supply of the fuel.

Chinese miners dug out 333.35 million tonnes of coal in June, up 10.4% from the same month in 2018, government data shows. The country's statistic bureau is due to release the July output numbers on Aug. 14.

Thermal coal prices on the Zhengzhou Commodity Exchange were little changed on Thursday at 577.8 yuan ($82.06) a tonne.