The thinning or reduction in total volume of ozone layer in earth’s stratosphere is referred to as Ozone layer depletion.
A ‘hole” in the ozone layer is detected over Antarctica. The bromine and chlorine gases destroys the ozone molecules.
Ozone is continuously created by absorption of short wavelength UV radiation. At the same time, it is removed by certain chemical actions because, 03 (ozone) is converted into molecular oxygen. The rates of creation and removal at any given time and location determine the ozone concentration in the stratospheric zone. Certain substances like chlorine, nitrogen and bromine act as catalysts and enhance the removal process. This process is known as ozone depletion.
Source: The main gases responsible for ozone depletion are chlorofluorocarbons (CFC) and Hydrochlorofluorocarbons (HCFC). CFC molecules can be broken down by UV radiation, free the chlorine, which acts as catalysts that destroy ozone. One chlorine molecule can destroy tens of thousands of ozone molecules.