Concerns raised over ‘micro-management’ of air quality data
As smog blankets the national capital, Delhiites continue to complain of burning eyes, scratchy throats and breathing difficulties. The toxic haze has once again brought attention to the accuracy of the city’s official air quality data. Media reports have pointed out glaring inconsistencies and questionable practices near several monitoring stations, raising doubts about the credibility of pollution readings. Last month, an online survey of 14,978 residents revealed that 87 per cent have little or no trust in the AQI data released by the government. While 62 per cent said they had no trust and 25 per cent reported low trust, only 13 per cent expressed average or higher trust, reflecting a credibility gap in official air quality monitoring. Amid these concerns, allegations that the authorities might be “micro-managing” pollution readings by spraying water near monitoring stations have sparked debate about whether such actions could distort air quality data. Delhi’s Environment Minister Manjinder Singh Sirsa, however, defended the practice. “How would we suppress the dust? It’s natural- through sprinkling. It is being done throughout the city, including around stations. We are successfully able to control pollution,” he said. But experts warn that such measures, if done excessively near monitors, can be misleading. Dr Mohan P George, Consultant for Clean Air and Sustainable Mobility at the Centre for Science and Environment (CSE) and former Additional Director at the Delhi Pollution Control Committee, explains that India’s AQI is based on the concentration of pollutants such as PM2.5, PM10, nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3), and lead. “At least three parameters are required to calculate AQI,” he said. “Usually, PM2.5, PM10, and NO2 are used. The data from continuous analysers is converted into an index value ranging from 0 to 500 - from ‘good’ to ‘severe,’ with corresponding colour codes and public advisories.” The Central Pollution Control Board (CPCB) operates Delhi’s Continuous Ambient Air Quality Monitoring Stations (CAAQMS), which automatically transmit real-time data every few minutes. There are currently 39 such stations across the city.
