Finalized in 1987, the Montreal Protocol came into effect in 1989. Parties then agreed on the Kigali Amendment to the protocol in 2016, which aimed to gradually reduce the consumption and production of HFCs, based on the consensus that they are powerful greenhouse gases.

ODS are widely used in foam-blowing agents and refrigerants. HFCs, which do not deplete the ozone layer nearly as much, are used as replacements for some of them.

Hu Jianxin, a professor with the College of Environmental Sciences and Engineering at Peking University, said China has made significant progress in reducing ODS to protect the ozone layer.

It has published a series of documents to support the implementation of the 2010 regulation on ODS, including lists of controlled ODS and ODS subject to import and export control, he said.

To date, Hu said, China's reduction in ODS accounts for over half of the total reduction contributed by developing nations.

According to an assessment report compiled by the World Meteorological Organization and the United Nations Environment Programme, the ozone layer over the world's mid-latitude region is expected to recover to 1980 values by around 2045, he said.

Making the regulation cover HFCs means China will make an even greater contribution to reducing emissions of the powerful greenhouse gases, Hu said.

China is a major producer, consumer and exporter of HFCs, with Chinese-made refrigeration and air conditioning equipment containing the heat-trapping gases exported to most countries around the world, he said.

By promoting green alternatives to HFCs in sectors such as refrigeration, fire control and semiconductors, Hu said China will have a profound impact on the global reduction of HFC emissions.