New Delhi: A change in wind direction reduced the contribution of stubble burning to the pollution and it improved Delhi’s air quality slightly on Wednesday (November 11). The capital city recorded an air quality index (AQI) of 344, while the 24-hour average AQI was 476 on Tuesday.
Notably, an AQI between 201 and 300 is considered ‘poor’, 301-400 ‘very poor’ and 401-500 ‘severe’, while the AQI above 500 falls in the severe plus category. Delhi has witnessed six consecutive ‘severe’ air quality days till Tuesday. It had recorded seven such days in November last year.
The neighbouring cities of Faridabad (327), Ghaziabad (360), Noida (309), Greater Noida (340), and Gurgaon (288), which fall in the National Capital Region (NCR), also recorded their AQI in ‘poor’ and “very poor” categories on Wednesday.
The Central Pollution Control Board (CPCB) ordered the closure of hot mix plants and stone crushers in Delhi-NCR till November 17 in view of a likely increase in pollution levels during the coming days, when a number of festivals will be celebrated.
It also asked the governments of Punjab and Haryana to take immediate stringent actions to curb stubble burning and authorities in Delhi-NCR to strictly check biomass burning.
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 ?g/m3 and 500 ?g/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 the National Capital Region and Adjoining Areas on Tuesday tasked the CPCB with operationalising and monitoring GRAP measures till a mechanism is set up by the newly-constituted panel.
The Ministry of Earth Sciences’ air quality monitor, SAFAR, said the change in transport level wind direction has led to a significant decrease in stubble burning-related intrusion in spite of high fire counts.
The farm fire count in Punjab, Haryana, Uttar Pradesh, Uttarakhand, and neighbouring areas was 2,422 on Tuesday and the share of stubble burning in Delhi’s PM2.5 accumulation is almost negligible — 3 percent – on Wednesday due to unfavourable transport-level winds, it said, adding “Deterioration (in air quality) is expected on Friday towards the higher end of the ‘very poor’ category.”
An official of the India Meteorological Department (IMD) said the predominant wind direction is east-northeasterly, which is not favorable for the transport of pollutants from farm fires in Punjab and Haryana.
The city recorded a minimum temperature of 11.4 degrees Celsius on Wednesday morning. Calm winds and low temperatures trap pollutants close to the ground, while favourable wind speed helps in their dispersion.
The central government’s Air Quality Early Warning System for Delhi said, “The change in wind direction and wind speed has positively impacted air quality. It is likely to remain in the upper end of the ‘very poor’ category on Thursday and deteriorate marginally on Friday.”
Air pollution a silent killer: Randeep Guleria
Noting that air pollution is a silent killer, Randeep Guleria, Director at the All India Institute of Medical Sciences (AIIMS), has said that it contributes to up to 40 per cent deaths in patients with chronic illnesses and neonatal fatalities.
Guleria is quoted as saying by IANS, “The global burden disease published in Lancet shows that in 2019, air pollution was the fourth leading cause of mortality and third for disability-adjusted life years. Air pollution is a silent killer which makes it difficult for the policymakers to understand.”
Dr Guleria said, “We must focus more on the chronic effects of pollution such as diabetes, lower respiratory tract disease, lung cancer, stroke or neonatal deaths – there is enough data to say that around 20 to 40 per cent of deaths in these diseases are caused by air pollution,” while addressing the second Good Air Summit organised by the Integrated Health and Wellbeing (IHW) Council.
The AIIMS chief also shared that within a few days of spike in air pollution levels, the influx of patients increased in the hospital`s OPDs.
(With Agency Inputs)