kheldan quotes a report from BBC: Researchers say they have found the first clear evidence that the thinning in the ozone layer above Antarctica is starting to heal. The scientists said that in September 2015 the hole was around 4 million sq km smaller than it was in the year 2000 -- an area roughly the size of India. The gains have been credited to the long term phasing out of ozone-destroying chemicals. [The study also sheds new light on the role of volcanoes in making the problem worse.] The ozone-destroying chemicals, chlorofluorocarbons (CFCs), have been shown to be declining in their influence, causing the ozone layer to grow once more. "Even though we phased out the production of CFCs in all countries including India and China around the year 2000, there's still a lot of chlorine left in the atmosphere," Prof Solomon told the BBC World Service Science in Action program. "It has a lifetime of about 50-100 years, so it is starting to slowly decay and the ozone will slowly recover." Scientists also believe that volcanic sulphur can form tiny particles that act as seeds to Polar Stratospheric Clouds, where chlorine chemistry occurs that destroys the ozone.