On Friday morning, the air quality in the national capital jumped to 472. In Noida and Gurugram, it stood at 562 and 593 respectively — an abnormally high level. It meant that the people were effectively breathing smoke.
In some pockets of the city, the index exceeded 800, according Delhi Pollution Control Committee findings.
According to the Centre, a reading of over 400 affects healthy people, with serious impacts on those with existing diseases.
Pushing the limits
Air quality in parts of Delhi is now consistently over 500, which is the maximum limit defined by the Centre. Beyond this, the air turns severely toxic.
There are six AQI categories, namely Good, Satisfactory, Moderately polluted, Poor, Very Poor, and Severe.
The AQI considers eight pollutants present in the air (PM10, PM2.5, NO2, SO2, CO, O3, NH3, and Pb) for which short-term (up to 24-hourly averaging period) National Ambient Air Quality Standards are prescribed.
An AQI between zero and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.
On Friday, Delhi’s 24-hour average air quality index spiralled to 450, just a notch short of the “severe plus” category.
According to the Centre, an AQI in the severe category can cause respiratory impact even on healthy people as well as serious health impact on people with lung/heart disease.
The health impacts can be experienced even during light physical activity.
Why is Delhi air so poisonous
The primary reason behind Delhi’s bad air is stubble burning.
According to SAFAR (System of Air Quality and Weather Forecasting And Research), stubble burning contributed 34 per cent in Delhi’s PM 2.5 pollution.
The burning of rice paddies after harvests across Punjab and other states persists every year despite efforts to persuade farmers to use different methods.
This is because farmers have to clear their fields ahead of the rabi season and burning of stubble is an efficient – and quickest – way to do it.
The widespread stubble burning in Punjab is actually a groundwater issue.
In Punjab, farmers are prohibited from planting paddy in May in order to prevent groundwater levels from going low before the monsoons. Groundwater depleting is turning into a big problem in Punjab and paddy is a water-intensive crop.
Thus, farmers in Punjab can only plant paddy from mid-June onwards. This has a cascading effect.
Due to the late sowing, the crops are harvested only in late October/early November. This coincides with the onset of winter season in north India when wind speeds slow down and temperatures drop.
If the sowing happened in May, the crops would harvest in September, which is windier and warmer in comparison.
Plus, most farmers in Punjab are poor and cannot afford machinery for clearing out stubble in the ground. They are left with no option but to resort to the cheaper solution of stubble burning.
Delhi government steps in
With air quality projected to get worse in the coming days, the Delhi government has stepped in to implement curbs to alleviate the problem
Delhi chief minister Arvind Kejriwal, whose party also rules Punjab where crop burning is rampant, said on Twitter that the “people of Punjab and Delhi are taking all steps at their level” to tackle pollution.
Delhi environment minister Gopal Rai has suggested a 5-point plan to reduce pollution. He will convene a high-level meeting on Friday to discuss the implementation of curbs on polluting activities under the final stage of the Graded Response Action Plan.
(With inputs from agencies)