Click on the cities for the current ambient air quality data, presented as box plots (looking at the variation in concentrations within a day) and as time series (looking at the variation in concentrations by hour). These plots are updated every 30 minutes; for 6 criteria pollutants – Particulate Matter (2.5 and 10), Sulfur Dioxide (SO2), Nitrogen Dioxide (NO2), Carbon Monoxide (CO), and Ozone (O3).
Ambient monitoring data is pooled from multiple sources (only the sources with data feeds in the public domain). 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). Other networks are the following
- SAFAR program, maintained by the Indian Institute of Tropical Meteorological (IITM) and the Indian Meteorological Department (IMD)
- The United States Embassy, records and reports PM2.5 concentrations and AQI on an hourly basis, using MetOne BAM, in multiple cities
As of September, 2017, under the guidance of CPCB, there are 74 continuous air monitoring stations operating in 16 states and 43 cities – with 19 of these operating in and around the Greater Delhi region (Delhi = 14, and one each in Noida, Ghaziabad, Rohtak, Gurgaon, and Faridabad). Most of the cities have one station to represent the full array of criteria pollutants. This is inadequate as it generates a statistically insignificant sample to represent the city or the range of sources contributing to the air pollution problem in the city.
|State||# of Stations||District with at least one continuous monitor|
|1||Andhra Pradesh||5||Chitoor (1), Vijayawada (1), East Godavari (1), Vishakapatnam (2)|
|2||Bihar||3||Muzafarpur (1), Patna (1), Gaya (1)|
|5||Haryana||4||Panchkula (1), Faridabad (1), Gurgaon (1), Rohtak (1)|
|9||Maharashtra||9||Mumbai (2), Thane (1), Solapur (1), Pune (1), Nashik (1), Aurangabad (1), Nagpur (1), Chandrapur (1)|
|10||Odisha||2||Anugul (1), Jarsguda (1)|
|11||Punjab||3||Amritsar (1), Ludhiana (1), Fatehgrah (1)|
|12||Rajasthan||3||Jaipur (2), Jodhpur (1)|
|13||Tamil Nadu||3||Chennai (3)|
|15||Uttar Pradesh||9||Ghaziabad (1), Moradabad (1), Noida (1), Agra (1), Kanpur (1), Lucknow (3), Varanasi (1)|
|16||West Bengal||5||Kolkata (2), Howrah (1), Haldia (1), Durgapur (1)|
How many continuous monitors are recommended by district and by state?
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.
|State||Operational as of Sept 2017||Recommended # of Monitors||# urban-monitors||# rural-monitors||%urban-monitors|
|1||Jammu & Kashmir||0||91||34||57||37%|
|7||NCT of Delhi||14||77||77||0||100%|
|25||Daman & Diu||0||4||4||0||100%|
|26||Dadra & Nagar Haveli||0||4||4||0||100%|
|35||Andaman & Nicobar Island||0||4||4||0||100%|
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)
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