China's coal exports have kept declining since the beginning of the second half of this year, partly as a result of limits in export quotas.

According to latest customs data, China sold abroad 2.08 million tonnes of coal in September, down 53.6 percent from the 4.48 million tonnes in the same month of last year.

After the coal exports hit 6.99 million tonnes in June, the highest within the year, the foreign sales began to fall in July and continued the downward trend in August and September.

Industry observers said the foreign sales were limited by absence of second-batch quota.

In the first half of this year, China set the first-batch quota at 31.8 million tonnes, or 60 percent of its total coal exports for the whole of last year. But it declined to release the quota for the second half year as an effort to ensure domestic supplies.

Huang Teng, a coal trade analyst, said on Saturday that the new export quota would likely be issued within this month, so that exporters would be able to fulfill their contracts with importers from Japan and the Republic of Korea.

In the first three quarters, the coal exports stood at 35.72 million tonnes, down 6.1 percent from a year earlier, according to the General Administration of Customs. But the export value increased by 65.1 percent to $3.78 billion.