New Delhi: Of India’s 4,041 census cities and towns, a mere 12 percent have air quality monitoring systems. What’s more, only 200 of these cities monitor all six key criteria pollutants. This is when compliance with the National Ambient Air Quality Standards and clean air targets under the National Clean Air Programme requires robust air quality monitoring.

A new analysis by the Centre for Science and Environment released here recently has laid bare this abysmal state of the country’s air quality monitoring network.

The analysis points out that this means nearly 47 per cent of the country’s population remains outside the maximum radius of the air quality monitoring grid, while 62 per cent is outside that of the real-time monitoring network.

“Limited air quality monitoring makes it challenging to identify the non-attainment status of a vast number of towns/cities and regions and also impedes effective evaluation of clean air action and improvement in air quality needed for evaluation of the performance of clean air action, especially under the 15th Finance Commission grant. More harmful PM2.5 and ozone are not considered for compliance under NCAP due to limited monitoring and data. It is necessary to ensure more equitable distribution of monitors and adoption of hybrid monitoring with a standardised and certified air sensor network and satellite-based monitoring with appropriate protocols for maximum and cost-effective coverage of population to support action,” says Anumita Roychowdhury, executive director of research and advocacy, CSE.

“The current monitoring network also faces the challenge of inadequate data generation, lack of data completeness and poor quality control of monitoring. This makes air quality trend assessment difficult to establish compliance with clean air targets. The current urban monitoring grid is highly concentrated in a few big cities and there are vast areas in other regions with no monitoring. This needs to be rationalised to cover a wider population and habitats to support the implementation of clean air action plans, provide information to the public about the daily risks and design emergency response and longer-term action,” adds Avikal Somvanshi, senior programme manager of the urban lab, CSE.

CSE’s assessment has analysed the adequacy of the air quality monitoring network and air quality data, spatial spread, population coverage and data completeness in the country. This has considered both manual monitoring under the National Air Quality Monitoring Programme and real-time monitoring under the Continuous Ambient Air Quality Monitoring System. The key focus is on the adequacy and completeness of the PM2.5 data.

The study covers 883 manual stations and 409 real-time stations. It has accessed and analysed publicly available data from the websites and publications of the Central Pollution Control Board as of December 31, 2022.

Air quality reported by a station is understood to be an accurate representation of ambient air in its 2 km radius, while it can also be fairly representative of a 2-10 km radius around the station. Without major topographical or human-made features, the air quality reported at a station can also be a good proxy for ambient air 10-50 km around the station. This method is drawn from the 2019 UNICEF report on the assessment of coverage of children by monitoring stations in Africa that also accounts for the population overlaps.