Ozone hole - a local drop in the ozone content in the ozone layer of the Earth.
There are several hypotheses about the causes of a decrease in ozone concentration. The first is associated with human exposure. It was believed that the production of freons, chemicals that were used as coolants in refrigerators and air conditioners, has a negative effect on the ozone layer, decaying in the atmosphere under the influence of ultraviolet radiation from the sun.
