It is that time of the year yet again when Delhi becomes a veritable gas chamber for weeks. The city is shrouded in dense smog, the air has become too toxic to inhale, watering itchy eyes is a common symptom, and there is a rapid rise in people visiting doctors due to respiratory ailments.
The AQI ( Air Quality Index) in many parts of the city has reached 795 on PM 10 which is manifold times over the tolerable limits and falls under ‘hazardous’ levels. The worst is yet to come as two years back the quality index crossed 999. A public health emergency has been declared by the Supreme Court and all construction activities have been halted till November 5. Schools will also remain closed during this period.
While the Delhi-NCR region does have an issue with loose dust due to heavy construction activities, vehicular pollution and unregulated factories belching out smoke — all contributing to make the region one of the most polluted in the world — however, satellite imagery by Copernicus Sentinel 2A, 2B, NASA, and WRI establish that stubble burning in the agrarian belts of Punjab and Haryana is the main reason behind the drastic spike in pollution levels.
With the coming of cooler weather in November, the smoke from stubble mixes with fog, dust, and industrial pollution to form a particularly thick haze. A lack of wind, which usually helps disperse air pollution, further compounds the problem for several days in November.
Stubble – or the left-over agrarian waste – is burnt by the farmers of Punjab and Haryana after the harvesting is done. Burying the waste or vermicomposting it to make manure – as is done by farmers in many areas of Uttar Pradesh – is undoubtedly environmentally friendly and a better option, but it is also time-consuming and requires arduous labor. With crop rotation and two harvesting seasons a year nowadays, farmers have to clear the waste within a period of just 15 days, so they look for the most cost-effective method which also has the benefit of being least time-consuming.
As per a report released by UN last year, 14 out of the 15 most polluted cities are in India. And this trend shows no signs of abating. Air pollution has become the elephant in the room and nothing short of permanent, concrete steps and a determined will to act upon it with concerted efforts would suffice. For the denizens of Delhi combatting air pollution has become an existential necessity more than an issue of ecological sustainability