A senior official on June 25 called for the country to speed up mass production of shale gas with its own technologies to ensure adequate energy supply.

Efforts must be made to achieve early breakthroughs in the appraisal, exploration and development of shale gas resources, as well as to discover ways to ensure environmental safety, said Liu Tienan, head of the National Energy Administration.

Liu stressed that the shale gas industry should be open to all types of investors. The departments involved should offer tax and fiscal incentives to encourage development.

Shale gas, a clean and high-efficiency energy resource, is produced from shale through a complicated process called hydraulic fracturing. China's rich reserves of shale gas are estimated to amount to 31 trillion cubic meters, equivalent to the total amount of conventional natural gas.