An east China city has been nicknamed the "kingdom of rare earth" for its rich reserves of the precious resource.

Ganzhou, the second-largest city in Jiangxi province, was given the title for its unrivaled reserves of ion-absorption rare earths in the world, a local government official said Monday.

The city's title is expected to boost the sustainable development of the city's rare earth industry, the official said.

Thirty-six percent of China's middle and heavy rare earth reserves are in Ganzhou, which has experienced overexploitation since the end of the 1970s. The local government is making efforts to repair the city's environment.

The city will underline the efficient use of rare earth resources and step up environmental protection efforts while promoting the industry in the future, said the official.

The State Council, or China's cabinet, has issued a development guideline for southern Jiangxi in order to make the area an internationally competitive player in the rare earth industry.

According to a white paper issued in June this year, China produces more than 90 percent of the world's rare earth metals.

Rare earth metals are a group of 17 chemical elements used extensively in high-tech manufacturing. They are categorized as being light, middle and heavy according to their atomic weight and physiochemical properties.