Delhi's air quality on Diwali not as bad as previous years; Reason – stubble burning yet to touch peak

Chandigarh: In 2021, the national capital woke up to a smoggy and hazy morning the day after Diwali.

Recording the air quality index (AQI) of 460, the pollutant levels in Delhi were in the ‘severe’ category, with residents complaining of a number of ailments.

In 2020, Delhi's air quality was also in the severe category at 435.

This year Delhi’s air quality is not as bad as in previous years.

It recorded an AQI of 323 a day after Diwali on October 24, which otherwise falls in the very poor category but is considerably lower than the severe category of air pollution. 

The latest data busts several myths, which are often held accountable for air pollution in and around Delhi after the Diwali celebration.

First, the firecrackers are not solely responsible for turning the Delhi air toxic as it is often blamed. They are an important factor, but not a single major factor in making the Delhi air toxic. 

Second, when Diwali was celebrated last year on November 4, stubble burning was at its peak in Punjab, Haryana and UP.

These three states are most notoriously known for crop residue burning, which for the last many years has been deteriorating the air quality in Delhi and NCR, as several studies suggest.

The data obtained from the Indian Agriculture Research Institute (IARI) revealed that the combined number of stubble fires recorded in these three states from November 1 to November 4 in 2021 was 11,526 - 2,077 (Nov 1), 3,291 (Nov 2), 2,775  (Nov 3) and 3,383 (Nov 4). 90% of these cases were in Punjab alone.  

This year, stubble-burning cases in Punjab, Haryana and UP recorded three days prior to Diwali were precisely 66% less than what was recorded during the corresponding period last Diwali.

As per IARI data, the combined stubble fires on October 21 to October 24 in Punjab, Haryana and UP were 3,956 – 523 (Oct 21), 722 (Oct 22), 1228 (Oct 23) and 1484 (Oct 24).

So the prime reason for relatively finer air quality in Delhi was just because Diwali did not fall during the peak stubble burning season as seen in previous years.

Also, the delay in harvesting due to untimely rainfall in the last week of September and the second week of October prolonged the crop residue burning season in the region.

But it does not mean that the stubble-burning cases are not likely to reach the peak.

In the past few days, there has been a considerable jump in farm fires, especially in Punjab, which has almost doubled in the last four days from 582 cases on October 22 to 1019 cases on the day of Diwali on October 24.

Officials at Punjab Pollution Control Board, a monitoring agency to control farm fires, told NewsDrum that the coming days are very crucial for stubble burning.

The cases are likely to increase substantially as farmers start making preparations for sowing the next wheat crop after selling their paddy crop in a couple of days.