International Day for the Preservation of the Ozone Layer

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  • Published
    20th Sep, 2018


  • Every year on September 16, the International Day for Preservation of Ozone Layer (or World Ozone Day) is observed for the preservation of the Ozone Layer.
  • Theme for this year was‘Keep Cool and Carry On: The Montreal Protocol’.


  • The day was designated by United Nations General Assembly (UNGA).
  • Its observance commemorates the date in 1987 on which Montreal Protocol was signed on substances that deplete the ozone layer.
  • It is intended to spread awareness of the depletion of the ozone layer and search for solutions to preserve it.

Ozone layer

  • Ozone layer is a fragile shield of gas which protects the Earth by absorbing harmful ultraviolet (UV) radiation of Sun and thus helps preserve life on the planet.
  • Stratospheric ozone is not harmful, but its presence in troposphere is harmful.
  • Substances like Chlorofluorocarbons, Halons, Carbon-tetrachloride are considered as Ozone Depleting Substances (ODSs)
  • Dobson unit is a unit which is used to measure the ozone in the atmosphere at a standard temperature and pressure.

Montreal Protocol

  • It is an international treaty agreed in 1987 in Montreal, Canada and entered into force on 26 August 1989
  • It is designed to protect ozone layer by phasing out production of numerous ODSs that are responsible for ozone depletion.
    a. With Kigali amendment, it plans to reduce the manufacture and use of Hydrofluorocarbons (HFCs) by roughly 80-85% from their respective baselines till 2045.
  • It is legally binding on member countries.
  • It has been ratified by 197 parties making it universally ratified protocol in UN history.
  • It is termed as highly successful international arrangement, as it has phased-out more than 95% of the ODS so far. It has also helped in recovering the ozone hole in Antarctica.

Vienna Convention for Protection of the Ozone Layer

  • It is a multilateral environmental agreement agreed upon at the 1985 Vienna Conference and entered into force in 1988.
  • It acted as framework for international efforts to protect fragile ozone layer. These are laid out in accompanying Montreal Protocol.
  • However, it does not include legally binding reduction goals for the use of CFCs, the main chemical agents causing ozone depletion.
  • It is also one of the most successful treaties of all time in terms of universality and has been ratified by 197 states.

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