Context -

• World Ozone Day is celebrated every year on 16 September to bring awareness to the conservation of the ozone layer.
• The theme of World Ozone Day 2023 is -"Montreal Protocol: Fixing the Ozone Layer and Reducing Climate Change."

 Background -

• On September 16, 1987, the Montreal Protocol on Substances that Deplete the Ozone Layer was adopted.

 What is the ozone layer?

• There is a layer of the Earth's atmosphere in which the concentration of ozone gas is relatively high.
• Life on Earth is possible only because of the ozone layer.
• This layer absorbs 90-99% of the Sun's high frequency ultraviolet light, which is harmful to life on Earth.
• More than 91% of the ozone in Earth's atmosphere is present here.
• It is mainly located in the lower part of the stratosphere, more than 10 km above the earth's surface and up to a distance of about 30 km from the earth, although its thickness varies depending on the season and geography.

 Ozone Depletion -

• Scientific and authentic knowledge of ozone layer depletion was first given by American scientists Sherwood Rowland and Marion Mollica in 1973.
• According to them, the man-made gas chlorofluorocarbon (CFC) can destroy the ozone layer.

 Due to depletion of ozone layer -

• Among the natural factors, solar action, nitrous oxide, natural chlorine, atmospheric circulation, gases coming out from the creative plate edges of the earth and gases coming out from central volcanic eruptions are prominent.
• Among human factors, excessive use of chlorofluorocarbons or CFCs is responsible for the depletion of the ozone layer.
• These are emitted by soaps, solvents, spray aerosols, refrigerators, air-conditioners, etc.
• Apart from this, ozone layer is also damaged by halons (used as fire fighting elements) and carbon tetrachloride (used in cleaning).

 Effects of ozone layer depletion -

• The possibility of diseases like pneumonia, bronchitis, ulcer increases.
• Skin cancer due to exposure to ultraviolet rays from the sun.
• genetic anomalies due to ozone depletion,
• Occurrence of deformities and chronic diseases.
• Ultraviolet rays emanating from the sun cause fatal eye diseases - inflammation, cataract, wounds.
• Rise in temperature
• Negative impact on the food chain etc.
•  To stop the depletion of ozone layer
• Measures taken -
• Vienna Convention - 1985
• Montreal Protocol -1987
• Kigali Amendment (2016) – Parties to the Montreal Protocol agreed to reduce the production and consumption of hydrofluorocarbons (HFCs).

Exam oriented Static facts

• Montreal Protocol - 16th September, 1987
• India became party to the Montreal Protocol - June 1992