United Nations: Nitrogen Dioxide levels fell by 70% in Delhi.

28 July 2020.


According to a report by United Nations, levels of nitrogen dioxide fell by more than 70 per cent during the lockdown in New Delhi. However, it stated that the environmental gains could be temporary if the cities re-open without policies to prevent air pollution and promote de-carbonisation.


  • Nitrogen Dioxide levels have fallen down in other countries as well.
  • In China the levels have fallen by 40%.
  • In Belgium,it fell by 20% between  19- 40% in USA.

Harmful Effects of Nitrogen Dioxide:

  • Nitrogen oxides reduce the air quality.
  • It depletes the ozone layer (the stratospheric ozone) by combining with ammonia via particulate matter.
  • It also increases human health risks like cancer and other respiratory diseases.
  • The Nitrogen oxides can get converted into nitric acid and cause acid rain.
  • Acid rains are leech into underground surfaces contaminating ground water.

Major pollutants-Ground level Ozone and Nitrogen Dioxide:

  • 90% of the total ozone is present in the Stratosphere.
  • 10% is found in troposphere and is less concentrated than that of stratospheric ozone.
  • The Ground level Ozone is created by the chemical reaction  between organic compounds and nitrogen oxides.
  • Ozone being a greenhouse gas contributes to global warming.
  • Thus control of nitrogen oxides becomes imperative.

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