Air Quality Index

The Environmental Monitoring and Research Centre, which is a nodal agency for India Meteorological Department (IMD) and provides colour-coded air quality rankings for Delhi ranging from “good” to “severe.”

Prime Minister Narendra Modi on April 6 launched a National Air Quality Index (AQI), which will monitor the quality of air in major urban centers across the country on a real-time basis. The index is to be launched in 10 major cities, including Mumbai and New Delhi, with the aim of eventually covering 66 cities.

India ranks 155 of 178 countries in the report's Environmental Performance Index. A World Health Organization (WHO) study of 1,600 cities released last year showed that New Delhi has the world's highest annual average concentration of small airborne particles known as PM2.5 - higher even than the Chinese capital Beijing. India disputes the figures but has admitted that pollution levels are comparable.

The AQI has been developed for six pollutants – PM2.5, PM10, nitrogen oxides, sulphur dioxide, ozone, and carbon monoxide. Air pollution levels have been classified in six bands with simple descriptions to help people understand. Each band has cut points of concentration with a colour code to visually express the level of severity that people can comprehend easily.

Air quality is classified good if the pollution levels are at least 50 per cent below the regulatory standards.The new AQI has been hosted on the website of the Central Pollution Control Board. You can visit http://aqi.iitk.ac.in:9000/ to see the air quality of the cities in India. Soon industries across all sectors in the country will also be classified depending on the extent of pollution they cause.