The ozone layer
The ozone gas is a compound having three molecules of oxygen combined together. The oxygen in the upper reaches of the atmosphere due to the action of the ultraviolet rays breaks into the atomic oxygen. The free atoms of these readily combine with the other molecules of oxygen present nearby resulting into the ozone molecules. These ozone molecules act as a blanket of the earth by not letting the harmful ultra violet rays to get into the atmosphere. But due to the industry Emissions of Chlorofluorocarbons the ozone layer is being depleted and the blanket is getting thinner and thinner.