India's coal imports fell 5 percent in October in their fourth straight monthly slide as local output rose fast under the government's push to open a mine every month, keeping the country on course to become self-sufficient in thermal coal in three years.

Asia's third largest economy is targeting to more than double coal output to 1.5 billion tonnes this decade, and state-run Coal India has already turned around its poor performance with record growth from old and new pits.

Coal imports into India, the world's third-largest buyer, fell to 14.52 million tonnes last month from a year earlier, according to trade ministry data provided by Coal Secretary Anil Swarup. April-October purchases fell 4.6 percent to 108.4 million.

"The trend (of falling imports) will continue because of sustained increase in coal production by Coal India," Swarup told Reuters on Monday.

Apart from Coal India, Swarup expects about 500 million tonnes of coal coming from the private sector by the end of this decade. The government is working out details to open up the nationalized sector and allow private companies to mine and sell coal.

India has enough reserves of thermal, or power-generating, coal but will have to continue buying foreign coking coal used by the steel industry.