A little relief for Delhiites as the air quality marginally improves to ‘very poor’ category after being in the ‘severe’ category for six consecutive days. The slight relief is attributed to a change in the wind direction reducing the contribution of stubble burning in city’s pollution.
The national capital recorded the air quality index (AQI) of 388 at 9 am on Wednesday, November 11. However, the daily average AQI recorded on the previous day was 476.
In the National Capital Region, the AQI slipped to ‘very poor’ category with Faridabad recording AQI of 345, Ghaziabad 390, Noida 339, Greater Noida 322, and Gurgaon 309.
According to the Central Pollution Central Board (CPCB), the levels of PM2.5 were 233 µg/m3 at 9 am, below the emergency threshold of 300 µg/m3. And, PM10 levels stood at 384 µg/m3 at 9 pm. It had peaked to 685 µg/m3on Tuesday. PM10 levels below 100 µg/m3 are considered safe in India and 500 µg/m3 is the emergency threshold.
According to the Graded Response Action Plan (GRAP), the air quality is considered in the “severe plus” or “emergency” category if PM2.5 and PM10 levels persist above 300 µg/m3 and 500 µg/m3 for more than 48 hours.
GRAP recommends measures such as a ban on construction activities, entry of trucks and car rationing scheme in such a scenario.
The Commission for Air Quality Management in Delhi NCR and Adjoining Areas on November 10 tasked the CPCB with operationalising and monitoring GRAP measures till a mechanism is set up by the committee.
(With inputs from PTI)