Chlorofluorocarbons, or CFCs, are man-made chemical compounds that contain chlorine, fluorine, and carbon. They were commonly used in products like aerosol sprays, refrigeration, and air conditioning systems due to their stability and non-flammability. However, CFCs are harmful to the environment, particularly the ozone layer, which protects the Earth from harmful ultraviolet radiation. When released into the atmosphere, CFCs can rise to the stratosphere, where they break down and release chlorine atoms. These chlorine atoms can destroy ozone molecules, leading to ozone depletion. As a result, many countries have phased out the use of CFCs under the Montreal Protocol, an international treaty aimed at protecting the ozone layer.