The Ministry of Commerce (MOC) on Wednesday announced the second batch of rare earth export quota for this year, totaling 9,770 tons.

The latest quota, including 8,537 tons of light rare earth metals and 1,233 tons of medium and heavy rare earth metals, brings the full-year export quota to 30,996 tons, an increase of 2.7 percent from last year, according to data from the MOC.

The second quota will be granted to 24 companies, including the Baogang Group, the country's largest light rare earth producer, and the China Minmetals Corporation, according to an online statement from the MOC.

On December 27 last year, the ministry announced the country's first batch of rare earth export quota, totaling 10,546 tons for 11 qualified companies. The quota was later expanded by 10,680 tons.

Rare earth metals are vital for manufacturing an array of high-tech products, including cell phones, wind turbines, electric car batteries and missiles.

China supplies more than 90 percent of the world's rare earth metals, but its reserves only account for about one-third of the world's total. The mining of rare earth metals has caused severe environmental damage in several parts of China.

To reduce the environmental damage caused by rare earth exploitation, China has suspended the issuance of new licenses for rare earth prospecting and mining, imposed production caps and export quotas, and announced tougher environmental standards.