Since the late 1970s, the ozone layer has been damaged. This means that more of the sun's harmful UV radiation is able to reach the earth's surface. This radiation can cause sunburn, skin cancer and eye diseases. Go to the following link for more information about UV radiation . Halons, used as fire extinguishing chemicals, also destroy ozone.
Ozone depletion occurs over much of the planet.
These reactions happen on ice crystals in the very cold, high-altitude clouds above Antarctica. It is produced and destroyed naturally in the atmosphere and until recently, this resulted in a nicely balanced equilibrium. It is formed when oxygen molecules absorb ultraviolet radiation with wavelengths less than 240 nanometres and is destroyed when it absorbs ultraviolet radiation with wavelengths greater than 290 nanometres. The thickness of the ozone layer is measured in Dobson units. Divide the reading of stratospheric ozone in Dobson Units by 100 and you have the thickness in millimetres of a layer of pure ozone gas at ground level formed from all the ozone in the stratosphere at the time.