Though the Union Environment Ministry notified the ‘graded response action plan’ to combat air pollution in Delhi-NCR over four months ago, it does not seem to have had an impact, analysis of air quality data suggests.
The average air quality index for the period between April 24 and May 24 this year is 252, placing the city in the ‘poor’ air category. This figure is one point higher than the average of 251 recorded during the same time last year.
Analysis of the CPCB’s AQI bulletin archives also revealed that the number of days over the 31-day period categorised as having ‘very poor’ air was also more or less the same: seven days in 2017, up from six in 2016.
Similarly, 19 days were recorded as having ‘poor’ air quality days last year, while the figure this year is 18 days. The only significant difference is in traces of ozone picked up by monitoring stations. While nearly half the month last year revealed varying levels of ozone in the air along with other particulate matter, there have been only been two instances over the last month this year.
However, analysis of the archives also showed that data is not collected every day of the month from every functioning monitoring station. There are more than 12 monitoring stations across the city, run by the Delhi Pollution Control Committee, the CPCB and other agencies. For instance, April 20, 2016 was categorised as a ‘very poor’ air quality day at an index of 316 and traces of PM 2.5 were found in the air. This was, however, based on data from one monitoring station.
Noting that the trend appears to be similar across time frames, despite the notification of the graded response action plan, the Centre for Science and Environment’s Anumita Roychowdhury said, “The Delhi government should take action based on daily air quality levels. They need to expedite mechanisms for implementation of the action plan.”
The graded response lays down actions required to be taken as and when concentration of particulate matter or other pollutants reaches a certain level.
She also pointed out that summer months are a challenge given the impact of dust, dry-ash and traces of ozone which is harmful while at ground-level, for which there are controlled measures in the graded response action plan. “It is an issue that not every monitoring station is picking up the data,” Roychowdhury said. “Authorities must ensure proper maintenance is taking place so there are no data gaps.”
An EPCA member said raw data being used to estimate AQI should be made available in the public domain so it can be useful to regulators and activists. Currently, SAFAR, under the Ministry of Earth Sciences, is responsible for AQI estimation and display.