WHO-approved apps show AQI of 1,000; govt caps it at 500

Amid various factors being blamed for the failure of the government and pollution authorities to tackle poor air quality during winter, under-reportage of AQI figures has been cited as the key reason. With Central Pollution Control Board (CPCB) calculations capping the AQI reported at 500, local NCR environmental groups and Met scientists have demanded a revamp of AQI reportage for better policy framing and execution.

Many environmental groups of Gurugram and Faridabad have moved the CPCB, seeking an upgrade. “The WHO-approved apps show that AQI has risen even up to 1,000 in many areas while the government AQI sensor reports don’t budge beyond 500. When the air quality is 'very severe', government records say it's 'very poor', and thus steps are taken accordingly. This is impacting the health of people. We need to adhere to global systems of AQI calculation for better solutions,” said Ruchika Sethi of Clean Air Bharat.

Confusion marks 'bad air days' amid discrepancies between the figures reported by the CPCB and those from international sources, like Swiss air technology company, IQAir. The CPCB data never crosses 500 in its final calculation, however, globally accepted entities like IQAir reports AQI values consistently above 1,000, with some readings reaching as high as 1,500.

Met scientist Gufran Beig, Chair Professor, NIAS, and founder and project director of SAFAR (System of Air Quality and Weather Forecasting and Research), said: “CPCB puts a cap on the AQI, limiting it to 500. This means that even when concentrations exceed 500 micrograms per cubic metre, the AQI cannot go higher. There is a stark difference between official readings and other global monitoring systems, because India’s guidelines for converting mass concentration of pollutants to AQI figures are based on its own 'breakpoint', which are far less stringent than WHO-prescribed guidelines. Breakpoint is the threshold level from where AQI readings are set based on our epidemiological data and susceptibility studies that keep the Indian environment in mind. This would be fine, except for the discomfort of setting a cap at 500 AQI, regardless of how many times the concentrations exceed that level.”

Have taken up issue with Central board

"The issue has been raised many times. The air quality monitoring is centralised and we have asked the Central Pollution Control Board authorities to look into the matter and upgrade the systems, if required. Haryana is working hard to deal with AQI crises.” — Rao Narbir, state Environment Minister

WHO guidelines

Under Indian standards, PM 2.5 levels of 60 micrograms per cubic metre correspond to an AQI of 100, while WHO guidelines would categorise 50 micrograms per cubic metre as 100 AQI. Furthermore, CPCB’s calculations are based on 24-hour average concentrations, while IQAir reports AQI more frequently, which can lead to significantly higher readings.