Ozone layer depletion is a major phenomenon in :

Ozone layer depletion is a major phenomenon occurring in the stratosphere, the atmospheric layer extending from approximately 10 km to 50 km above the Earth's surface [2]. While ozone exists in both the troposphere and stratosphere, about 90% of atmospheric ozone is concentrated in the stratosphere, forming the 'ozonosphere' or ozone layer [5]. This layer is critical for life as it absorbs harmful ultraviolet (UV) radiation [5]. Depletion is primarily caused by human-made substances like chlorofluorocarbons (CFCs) and halons, which release chlorine and bromine radicals upon exposure to intense UV light [7]. These radicals catalyze chain reactions that break down ozone molecules, leading to the 'ozone hole' phenomenon, most notably observed over Antarctica [3]. Consequently, the stratosphere is the primary site for both the natural formation and the anthropogenic depletion of the ozone layer.

Sources

1. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Stratosphere (12 to 50 km) > p. 275
2. [4] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Structure of the Atmosphere > p. 7
3. [5] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 19: Ozone Depletion > OTSNE $$FUETION > p. 267
4. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Ozonosphere > p. 276
5. [3] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 11: World Climate and Climate Change > Greenhouse Gases(GHGs) > p. 96
6. [7] https://csl.noaa.gov/assessments/ozone/2022/twentyquestions/