The ozone is a type of oxygen formed in the upper atmosphere that helps block harmful radiation from the sun and forms a protective layer around the globe. In over Antarctica, a huge ozone hole develops each spring. The protective layer is being destroyed. The following is the culprit:

Reactive  Chlorine attacks the ozone when sunlight hits the polar air in the spring. Chlorine  comes from a range of useful compound called CFC's used widely for refrigeration and industrial processors. When old refrigerators are trashed, the CFC's escapes into the atmosphere. With less protective ozone, more harmful radiation gets through. Too much sun particularly around noon can lead to skin cancer. Everyone needs to be careful about sunbathing, particularly those with fair skin. In 1997, Montreal protocol stated that CFC emissions should be reduced by 50% by the year 2000 (they have been increasing by 3% per year). This agreement was amended  in London in 1990 to state that production of CFC's and CC14 and Halons should cease entirely by the year 2000. Happily there are some good news. In 1991, most of the world's government agreed to faze out CFC's.