Why in News?

• As Delhi chokes, the government has shut all schools till November 5 after a Supreme Court-mandated panel declared a public health emergency in Delhi-NCR.

Highlights:

• Air quality in the national capital saw a sharp dip after Diwali celebrations and has been deteriorating gradually as stubble burning continues in parts of Punjab and Haryana despite a ban.
• The blanket of haze over Delhi continues with the national capital’s pollution levels around the 450-mark.
• The overall AQI in Delhi was 427.
• Pollution levels in the satellite towns of Ghaziabad (496), Greater Noida (496), and Noida (499) were much worse.

AQI (Air Quality Index):

• The AQI is an index for reporting daily air quality.
• The AQI focuses on health affects you may experience within a few hours or days after breathing polluted air.
• EPA (Environment Protection Agency) calculates the AQI for five major air pollutants regulated by the Clean Air Act:
  • Ground-level ozone
  • Particle Pollution (also known as particulate matter)
  • Carbon Monoxide
  • Sulphur Dioxide, and
  • Nitrogen Dioxide.
• For each of these pollutants, EPA has established national air quality standards to protect public health.Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country.