India’s air quality data for comparing annual pollution is patchy

Representative image. File   | Photo Credit: Sushil Kumar Verma

The base data available for monitoring trends in air pollution from 2016-2019 is irregular in most of the States in which the 102 cities that have been targeted for improving air quality are situated. The was shown by an analysis of Central Pollution Control Board (CPCB)-data by Carbon Copy and Respirer Living Sciences, which are research and advocacy organisations working on analysing air pollution trends.

Only 15 States have PM(Particulate Matter)2.5 monitoring systems for any year. Only West Bengal has an above average number of readings available at 110 each for five monitors. Delhi ranks as the most polluted in PM2.5 average across all three years, followed by Uttar Pradesh and Bihar.

Out of the 23 States listed in the National Clean Air Programme (NCAP) only three States/Union Territories — Chandigarh, Himachal Pradesh and Punjab — accounted for above-average readings for all three years for PM10 monitoring.

Jharkhand was at the bottom of the chart with only 64 average readings per monitor, with three monitors accounted for in the State.

The NCAP envisages reducing air pollution levels by 20%-30% in 102 cities by 2024, based on 2017 levels of PM2.5 and PM10. Until 2018, the standard way cities measured pollution was the manual method in which readings from monitoring stations were compiled twice a week, for 52 weeks. Ideally, all of the cities ought to have 104 readings, from every monitor, every year, but this was rarely the case, and this data discrepancy would affect accurate comparison of year-wise changes in pollution levels. There is also a wide variation in the number of monitors in cities. After 2018, cities have begun moving to automated systems that continuously track and report pollution levels.

“While everyone relies on continuous monitoring of data, the Continuous Ambient Air Quality Monitoring Standards (CAAQMS) is a relatively new monitoring network, so if you want to compare levels in 2022 with those in 2018, there might not be enough data to do so,” said Santosh Harish, Fellow, Centre for Policy Research. “Tracking annual average concentrations provides an objective way to verify whether air quality levels have improved or not.”

59 out of 122 cities had no PM2.5 data available at all. Where data was available, Noida ranked the worst with an average PM2.5 reading of 119, followed by Agra, Delhi, Lucknow, Ghaziabad, Muzzaffarpur, Kanpur, Chandigarh, Howrah and Kolkata. Varanasi missed the top 10 by one spot, ranking a close 11th.

The NAMP (National Air Quality Monitoring Programme) has been running since 1984. However, the publicly reported data on the CPCB website is only available since 2016 till October 2019. India has a network of 793 NAAQS stations covering 344 cities/towns in 29 States and six Union Territories. Under NAMP, four pollutants — Sulphur dioxide (So2), Nitrogen dioxide (No2), suspended particulate matter (SPM), and respirable suspended particulate matter (RSPM) have been identified as key pollutants for regular monitoring.

The monitoring is being carried out by State Pollution Control Boards and the National Environmental Engineering Research Institute, Nagpur, and overseen by Pollution Control Committees, the CPCB, and now by the Union Environment Ministry under the NCAP.

Printable version | Nov 27, 2020 12:53:33 AM | https://www.thehindu.com/sci-tech/energy-and-environment/indias-air-quality-data-for-comparing-annual-pollution-is-patchy/article32964922.ece

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