English PSSSB Practice 30

Ozone depletion refers to the thinning and reduction of the ozone layer in the Earth's stratosphere, which protects life by absorbing most of the Sun's harmful ultraviolet (UV) radiation. The depletion of the ozone layer is a serious environmental concern as it increases the risk of skin cancer, cataracts, and damage to plants and marine life. The main causes of ozone depletion are human-made chemicals known as ozone-depleting substances (ODS), which include chlorofluorocarbons (CFCs), halons, carbon tetrachloride, methyl chloroform, and hydrochlorofluorocarbons (HCFCs). CFCs, once widely used in refrigeration, air conditioning, foam production, and aerosol sprays, are the primary contributors. When released into the atmosphere, these chemicals slowly rise to the stratosphere, where UV radiation breaks them down, releasing chlorine and bromine atoms. These atoms react with ozone (O3) molecules, causing their breakdown into oxygen (O2), thereby thinning the ozone layer. Halons, used in fire extinguishers, release bromine atoms that are even more destructive to ozone than chlorine. Other substances like methyl bromide and carbon tetrachloride, used in fumigation and industry, also release ozone-depleting halogens. Natural factors such as volcanic eruptions and solar activity can also affect the ozone layer, but their impact is minor compared to human-made causes. The depletion of the ozone layer is most pronounced over the polar regions, especially Antarctica, where extremely low temperatures and specific atmospheric conditions cause the annual formation of the "ozone hole." International cooperation to reduce and eliminate ODS has been formalized in the Montreal Protocol (1987), which aims to phase out the production and use of these harmful substances. Despite progress, ozone depletion remains a significant environmental problem, requiring continued global effort, technological innovation, and strict enforcement of international agreements. Public awareness, alternative technologies, and sustainable practices are essential to protect the ozone layer and ensure the health of the planet and all living beings.