Continuous air quality monitoring stations (CAAQMS) report data at 15-minute intervals and the data is posted on the CPCB portal in real time.

There are a total of 512 CAAQMS in India as of February, 2024.

Manual monitoring stations are those that report daily averages of select pollutants for at least 103 days in a year.

There are a total of 883 manual stations in India as of February, 2023.

The number of Indian cities reporting AQI in the bulletins increased 10-fold between 2015 and 2023.

However, most of these cities only have one monitoring station.

A city needs atleast 5 stations to cover one location each at residential, commercial, industrial, roadside, and background sites to provide a representative sample.

In 2023, only metropolitan and some Tier-1 cities, reported more than 5 stations.

These 15 cities are – Agra (6), Ahmedabad (9), Bengaluru (13), Chennai (8), Delhi (39), Hyderabad (14), Jaipur (6), Jodhpur (5), Kolkata (7), Lucknow (6), Moradabad (6), Mumbai (28), Navi Mumbai (7), Patna (6), and Pune (8).