The Union Minister for Environment, Forest and Climate Change recently commented on the issue of air pollution, noting that it is not solely a problem of Delhi and its corporations. Rather, it pertains to a vast airshed that includes the National Capital Region (NCR). This airshed, according to geographical definitions, is a region where the atmosphere shares common features regarding the dispersion of pollutants. In simpler terms, it denotes a region sharing a common flow of air.
Definition and Scope of Airshed
In relation to the prevailing air pollution in and around Delhi, this airshed comprises Gurgaon, Faridabad, Ghaziabad, Noida, as well as certain areas in Uttar Pradesh, Haryana, and even Alwar in Rajasthan.
Current Air Quality Status
As per recent data, the Air Quality Index (AQI) of Delhi falls within the ‘poor’ category. However, the Central government’s System of Air Quality and Weather Forecasting And Research (SAFAR) expects the AQI to hover between the higher end of ‘poor’ and the lower end of ‘very poor’ in the coming days. Interestingly, during the lockdown period, Delhi experienced some of its cleanest air since comprehensive records started being maintained in 2015.
Reasons for Air Pollution in Delhi
Air pollution in the Delhi-NCR and Indo Gangetic Plains is a complex phenomenon with multiple factors at play. For instance, the predominant wind direction during October, typically the time for monsoon withdrawal in Northwest India, is northwesterly – a pattern also seen in summers. This carries dust from northern Pakistan and Afghanistan. Additionally, winter’s slower wind speeds compared to summer makes the region more prone to pollution.
The Role of Stubble Burning
Other factors include stubble burning in states like Punjab, Rajasthan, and Haryana, which leads to a thick smog blanket over Delhi during winters. This practice, used to quickly and cost-effectively clear paddy stubble, releases harmful gases such as methane (CH4), carbon monoxide (CO), volatile organic compounds (VOC) and carcinogenic polycyclic aromatic hydrocarbons into the atmosphere.
Impact of Vehicular Emissions and Dust Storms
Vehicular pollution significantly contributes to the deterioration of Delhi’s air quality in winters, with around 20% of PM2.5 in winters originating from it. Dust storms from Gulf countries worsen the already poor condition, and between October and June, the prevalence of dust in the region due to dry cold weather doesn’t help. Consequently, dust pollution contributes to approximately 56% of PM10 and the PM2.5 load.
Firecrackers and Low Temperatures
Substantial pollution is also caused by firecrackers on Diwali, construction activities, and open waste burning at landfill sites. As temperatures dip, the inversion height is lowered, resulting in higher pollutant concentrations. The inversion height is a layer beyond which pollutants cannot disperse into the upper layer of the atmosphere.
Measures Taken to Address Pollution
Several measures have been taken to curb this growing problem. These include subsidies to farmers for acquiring Turbo Happy Seeder (THS), introduction of BS-VI vehicles, promoting electric vehicles, implementing emergency measures like Odd-Even, constructing peripheral expressways, and executing the Graded Response Action Plan (GRAP). The development of National AQI for public information under the Central Pollution Control Board (CPCB) is another significant step in tackling this issue.
The Way Forward
An active political will and an aware citizenry are vital for effectively dealing with air pollution. The pollution targets should be made public each year for the citizens to review, and their implementation evaluated at year-end. Prioritizing human health is essential in tackling air pollution, as breathing clean air is a fundamental right of every Indian citizen.
