BEIJING - China's environmental department on Wednesday promised to do more to control the emission of ozone layer depleting substances.

Chen Jining, Minister for Environmental Protection, told a meeting that China will eliminate the use of ozone layer depleting substances, industry by industry with clear deadlines.

The government will offer preferential policies for small business that are willing to replace outdated technology with more eco-friendly varieties, Chen said.

He also promised that his department will uphold the law and monitor the supply, application, import and export of chemicals that can harm the ozone layer.

This year marks the 30th anniversary of the Vienna Convention for the Protection of the Ozone Layer.

The Earth's protective ozone layer is on track to recover in the next few decades thanks to concerted international action, according to a report from the United Nations Environment Program (UNEP) and the World Meteorological Organization (WMO) last September.

The effort led to decreases in the atmospheric abundance of gases, such as CFCs (chlorofluorocarbons) and halons, once used in products such as refrigerators, aerosol sprays and insulation foam.