Answer: Ozone depletion refers to the gradual thinning of the ozone layer in the Earth's atmosphere.
Explanation: The ozone layer is a region of the stratosphere that contains relatively high concentrations of ozone (O3) molecules. This layer plays an important role in protecting the Earth from harmful ultraviolet radiation from the sun, which can cause skin cancer, cataracts, and other health problems. Ozone depletion occurs when chemicals such as chlorofluorocarbons (CFCs) and other halocarbons are released into the atmosphere. These chemicals can react with ozone molecules, causing them to break down and reducing the overall concentration of ozone in the atmosphere. Human activities, such as the use of CFCs in refrigeration, air conditioning, and aerosols, have been the primary cause of ozone depletion. The thinning of the ozone layer has significant environmental and health consequences and has led to increased efforts to reduce the use of CFCs and other ozone-depleting substances.