Air pollution in Delhi: the haze over AQI data blunts clean-up action

The haze over the accuracy and integrity of Delhi’s pollution data will also likely erode the effectiveness of pollution control measures

After the air quality index (AQI) in the national capital region (NCR) slipped into the “severe” category on Tuesday — having hovered close to this level for days — stage 3 of the Graded Response Action Plan (GRAP 3) was finally enforced. On Wednesday, too, the national capital’s AQI remained in the severe category. Whether GRAP 3 will lift some of the grey haze blanketing the region remains to be seen. The Supreme Court directed Punjab and Haryana on Wednesday to submit details of action taken against farm fires next week, and it is likely that farmers, especially in the former, will see this as a deadline and scramble to set fire to the remaining crop stubble in their fields.

Whether GRAP 3 will lift some of the grey haze blanketing the region remains to be seen. (ANI)

The haze over the accuracy and integrity of Delhi’s pollution data will also likely erode the effectiveness of pollution control measures. As this newspaper has repeatedly shown, there have been several recent instances of monitoring stations in the national capital falling silent, leading to significant data gaps. Similarly, there have been multiple points of deficiency in source-apportioning estimates from the Decision Support System, which is run by the Indian Institute of Tropical Meteorology, Pune.

Improbable spikes and falls and odd patterns in measurement, read together with algorithmic loopholes, raise doubts about the AQI data’s integrity. The Commission for Air Quality Management — the NCR pollution watchdog has turned a blind eye to these — and the political establishment must dispel the doubts with detailed clarifications, not dismissive rhetoric. Given the clear human cost of pollution, the response to deteriorating air quality must be scientifically calibrated. But that can only happen if the data is incontrovertible. As long as the data’s sanctity remains suspect, responses will likely be inadequate and tardy, exacerbating the harm.