Light Pollution

Light Pollution

Last Updated: March 2023

This article deals with ‘Light Pollution – UPSC.’ This is part of our series on ‘Environment’, which is an important pillar of the GS-3 syllabus. For more articles on Science and technology, you can click here.


Light Pollution
Light Pollution
  • Light Pollution is excessive & misdirected artificial (usually outdoor) light in the environment. 
  • It is also known as photo pollution or luminous pollution. 
  • 2017 WWF Earth Hour has highlighted the issue of Light Pollution.

Causes of Light Pollution

  • Unnecessary use of artificial lights
  • Poorly designed residential, commercial, and industrial outdoor lights. 
  • Unshielded light fixtures that emit more than 50% of their light skyward or sideways. 

Effect of Light Pollution

Effect of Light Pollution

1. Environment

  • Photo pollution increases air pollution by suppressing a naturally occurring Nitrate radical that cleans the air at night. (Nitrate prevents ground-level Ozone formation). 

2. Human Health

  • Light Pollution affects circadian rhythms (biological watch). 

3. Energy

  • Misdirected light results in energy waste and creates GHG emissions.

4. Wildlife

  • Lights can attract or repel animals and insects in human areas. 
  • It disturbs the migration of birds that navigate using the stars.

5. Astronomy

  • Light spills and sky glow interfere with astronomical equipment, making viewing faint celestial bodies difficult.

International Steps

  • 2017 WWF Earth Hour Highlighted the issue of Light Pollution.
  • Various NGOs like International Dark-Sky Association (IDA) (US-based NGO), Globe at Night, The World at Night etc., are also working in this regard.
  • Various local governments are also taking steps in this regard. For example, Philadelphia city (USA) has decided to dim the lights of Skyscraper buildings at night to prevent migratory birds from getting disoriented and crashing into the glass.  


The sky belongs to everyone and we should do what we can to make sure its the best possible sky we can see.

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