The Montreal Protocol, established in 1987, is a landmark international treaty aimed specifically at phasing out substances that deplete the ozone layer, such as chlorofluorocarbons (CFCs) and halons. This agreement reflects a global commitment to environmental protection and sustainable development, as it not only focuses on controlling harmful chemicals but also facilitates the transition to safer alternatives, thereby contributing to the protection of human health and the environment. The success of the Montreal Protocol demonstrates effective international cooperation in addressing the challenges of climate change and biodiversity loss, which are critical components of the UPSC GS Paper I syllabus under environmental studies.