What is stratosphere?

The stratosphere is just above troposphere and below mesosphere, which is the second most layer of the earth from the surface. The stratosphere starts just above the troposphere and extends 50km (31miles)

In stratosphere the temperature increases with increasing height just opposite of troposphere. Which means warmer layer is higher and colder layer is lower. This happens only because of the presence of ozone layer which is present in this layer

The ozone layer protect us from ultraviolet rays produced by the sun, which can cause skin cancer. So we can say this layer is very important for all living organisms. But because of Chlorofluorocarbons (CFCs) and halons gases formerly found in aerosol spray cans and refrigerants are released into the atmosphere hence causing depletion of the ozone layer.