India – Ambient Air Monitoring Data

The continuous monitoring stations accessed for this exercise are operated and maintained by the Central Pollution Control Board (CPCB) and the State Pollution Control Boards. All the data from these stations is available from CPCB website. A secondary source to download archived data is @ http://www.openaq.org (this is a portal with open access to monitoring data from stations across the globe; and also allows you to download data for select station or city or time period; compare data between stations, between cities, visualize the trends spatially and temporally, and much more). Plots below are updated once a day showing the 24-hr average for the previous day. The color code represents the Air Quality Index (AQI) scales of India.

How many continuous monitors are recommended by district and by state?

As of September 2019, under the guidance of CPCB, there are 200 continuous air monitoring stations operating in 20 states and covering 116 districts with at least one monitor. The current capacity to monitor air quality in Indian districts is inadequate as it generates a statistically insignificant sample to represent the district or the range of sources contributing to the air pollution problem in the district (except for the states like Delhi where the majority of the monitors are in operation). Based on thumb rule proposed by CPCB and the district level urban and rural population (as per 2011 census), we estimate the need for 4,000 continuous monitoring stations (2,800 in the urban areas and 1,200 in the rural areas of the districts, as per 2011 census) to spatially, temporally, and statistically represent the PM2.5 pollution in the urban and the rural areas of India.

Air Quality Index (AQI)

AQI color code in the box plots is based on national methodology as proposed by the Central Pollution Control Board (New Delhi, India). It is very important to note that these index methodologies vary significantly between countries and it is not advised to compare AQI values between countries or cities; which can result in misleading understanding and/or measures. Here is an infograph showing a comparison of the break points practiced in India, China, and 4 other countries.

AQI for Indian cities is also reported by AQICN (a Chinese AQI portal) using their methodology for all the global cities. A different AQI is reported by the Indian Institute of Tropical Meteorology (IITM) based on their methodology developed under the national SAFAR program (click here for a how to use the SAFAR-Air app on phones)

Resource links

• A resource blog on how to access air quality monitoring data in India (2020)
• National Ambient Monitoring Program (NAMP) – manual monitoring network operated and maintained by CPCB, India
• Continuous Ambient Air Quality Monitoring System (CAAQMS) – real-time monitoring network operated and maintained by CPCB, India
• openaq.org – aggregator of official real-time monitoring data across the globe (blog piece on how to access data)
• IQair – aggregator of official and unofficial data across the globle
• Breezo.in – aggregator of official real-time monitoring data in India
• AirVeda – unofficial network of low-cost sensors
• AQI.in – unofficial network of low-cost sensors
• Purple Air – unofficial network of low-cost sensors
• Clarity – unofficial network of low-cost sensors
• Blog pieces
  • March, 2016 – A call for open air pollution information
  • How do we improve Delhi’s graded responsibility action plan for better air quality, Op-Ed in the WIRE (2017) Download
  • It’s about time we got smarter about monitoring our air pollution? Op-Ed in the WIRE (2017) Download
  • The polluted air we breathe, Op-Ed in the Hindu (2015) Download