Effectively banned under the 1987 Montreal Protocol, CFC-11 is a Chlorofluorocarbon that destroys the ozone layer. Ozone depletion comes at a cost as greater UV penetration in the atmosphere can have for example a negative impact on human health.
Although CFC-11 particles can last up to 50 years in the atmosphere, a research team published a study in Nature demonstrating that the rate of decline in CFC-11 had slowed by about 50% after 2012. This slowdown could only be explained by one or more countries failing to apply the Montreal Protocol and falsifying their reports to the UN. An article on the subject was published in May 2018 in the Washington Post, however, at the time the source of these emissions was unknown. Suspicions were aimed towards companies that manufacture foam insulation the single largest emitters of CFC-11.
To identify the source, a UK-based NGO (The Environmental Investigation Agency) launched an investigation that found numerous Chinese foam manufacturers guilty of still using CFC-11 in their production process. In fact, 18 out of the 21 manufacturers that were interviewed admitted using the chemical because it was the cheapest solution (in 10 different provinces). Despite the investigation being covered extensively by Western media, it is still unclear what the consequences will be for these companies and the Chinese government. However, it is a good “test” for the Montreal Protocol.
Nathan Breen, Climate Analysis Team - Source: EIA, Financial Times, chinadialogue, Beyond Ratings