Crop Fires Not Behind Delhi Smog : Study Reveals Crop Fires in Punjab and Haryana Are Not the Cause of Air Quality Issues in Delhi-NCR

New Delhi, Feb 4 (NationPress) A recent study indicates that the elevated levels of PM2.5 in Delhi-NCR are largely unaffected by crop residue burning (CRB) occurring in Punjab and Haryana. This conclusion is drawn from research conducted by a team from Japan, utilizing data collected from a network of 30 monitoring sites.

As part of the Aakash Project led by the Research Institute for Humanity and Nature (RIHN) in Kyoto, the study reveals that even during the peak stubble burning season (October-November), crop fires are not the primary factor contributing to the poor air quality in the national capital and its surroundings.

For decades, the negative effects of air pollution on human health, economic activities, and daily life have been significant concerns, especially as pollution levels reach alarming highs every year in Delhi-NCR during the months of October and November.

Historically, substantial contributions from paddy CRB in the northwestern states of Punjab and Haryana have been cited as major contributors to the air pollution affecting the national capital.

Lead author Dr. Poonam Mangaraj from RIHN stated, “Our research emphasizes the necessity for ongoing air quality monitoring in source areas (Punjab), receptor areas (Delhi-NCR), and intermediate areas (Haryana) to implement effective mitigation strategies to address the persistent issue of harmful air pollution.”

The researchers concluded, “We have determined that CRB in Punjab and Haryana cannot be directly linked to air quality in Delhi-NCR, even during the peak rice stubble burning period (October-November).” This finding has been published in the journal npj Climate and Atmospheric Science.

The research team installed 30 compact and effective PM2.5 in situ instruments equipped with gas sensors (CUPI-Gs) to continuously monitor air pollutants in 2022 and 2023.

They analyzed a combination of (1) data from the low-cost CUPI-G network, (2) air mass trajectory analyses, fire counts, and wind patterns, along with (3) chemistry-transport simulations to evaluate the influence of CRB on PM2.5 levels in rural, suburban, and megacity areas.

The results show that despite a notable decline in satellite fire detection counts (FDCs) in Punjab and Haryana from 2015 to 2023, the PM2.5 levels in Delhi have remained consistently high.

In both 2022 and 2023, PM2.5 concentrations exhibited significant day-to-day variability across different monitoring sites.

During both years, substantial fire counts were recorded in southwestern Punjab, with daily average PM2.5 levels surpassing 300 micrograms per cubic meter in Delhi. However, the meteorological conditions varied significantly during the peak CRB days of November 1-12 for both years.

In November 2022, prevailing northwesterly winds facilitated the transport of air masses from Punjab and Haryana to Delhi-NCR on two separate occasions.

Conversely, November 2023 experienced southwesterly low wind conditions and limited airflow, resulting in the accumulation of local pollutants in Delhi-NCR.

The analysis indicates that the increase and persistence of PM2.5 levels in Delhi-NCR are primarily of local origin, as evidenced by fluctuations in line with the enforcement and lifting of the Graded Response Action Plan (GRAP) stages set by the Commission of Air Quality Management (CAQM).

Prof. Prabir Patra, the Aakash Project leader and principal scientist at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), noted, “With measurements from around 30 sites covering Punjab, Haryana, and Delhi-NCR, we can distinguish the contributions of paddy straw burning to the variations in PM2.5 levels in Delhi based on specific PM2.5 events and weekly to monthly averages.”