31st World Ozone Day | 17 Sep 2025

Why in News? 

The Union Ministry of Environment, Forest, and Climate Change (MoEF&CC) organized the 31st World Ozone Day in New Delhi on 16th September 2025. 

Key Points

  • About: World Ozone Day is observed on the 16th of September each year, commemorating the signing of the Montreal Protocol in 1987, a significant international treaty aimed at phasing out the production and consumption of Ozone Depleting Substances (ODS). 
  • Theme: The theme for 2025, ‘From Science to Global Action’, emphasizes the power of scientific discovery in policy formulation and international cooperation to protect the planet and its future.

Montreal Protocol Implementation

Ozone

  • The ozone layer, located in the stratosphere between 10 and 40 kilometers above Earth's surface, shields us from harmful UV radiation. 
    • This protective layer, known as stratospheric ozone or good ozone , prevents adverse health effects like cataracts and skin cancer and safeguards agriculture, forestry, and marine life. 
    • However, man-made Ozone Depleting Substances have caused ozone depletion in the stratosphere.
  • The international community recognized the need for action, leading to the Vienna Convention in 1985 and the subsequent Montreal Protocol in 1987. 
  • The inclusion of Hydrofluorocarbons (HFCs) in the Montreal Protocol led to the Kigali Amendment, with India ratifying it in September 2021. 

 Tropospheric Ozone

  • Tropospheric (or ground-level) ozone, or bad ozone, is a short-lived climate pollutant that remains in the atmosphere for only hours to weeks.
  • It does not have any direct emission sources; rather, it is a compound formed by the interaction of sunlight with volatile organic compounds (VOCs) – including methane – and nitrogen oxides (NOX) emitted largely by human activities.