BEIJING, May 7 -- China's coal sector has been hit by rising stockpiles, falling prices and declining profitability since the beginning of this year, an industry association said Wednesday.

In April, coal production dropped 1.31 percent year on year and sales dropped 1.29 percent, according to data released by the China Coal Industry Association (CCIA).

In the first quarter of 2014, coal output edged down by 1 percent to 878 million tonnes, while sales declined 1.4 percent to 844 million tonnes, the data showed.

Coal stockpiles at the end of last month totaled more than 300 million tonnes for the 29th consecutive month, according to the association.

The China Coal Price Index plunged 17.3 points year on year to 150.1 points on April 25. Combined profits of major coal miners plummeted 41.2 percent, while total losses climbed 39.7 percent, data showed.

Wang Xianzheng, director of the CCIA, said that coal demands in China dropped against the backdrop of the country's economic slowdown, accelerating transformation of energy structure, as well as rising resource and environmental constraints.

The industry should scientifically manage total coal output and make production arrangements based on changing market conditions, Wang said.

China's economic growth slowed to a six-quarter low of 7.4 percent in the first quarter of the year, down from an annual figure of 7.7 percent in 2013.