Impact of crop residue burning on regional air quality over the Indo-Gangetic Plain: a comparative study during...

The Indo-Gangetic Plain (IGP) in north India experiences severe seasonal air pollution from different crop residue burning (CRB) of the two different cultivation pattern such as wheat stubble in post-rabi (April-May) and paddy in post-kharif season (October-November). The present study evaluates the decadal impacts of CRB during the post-rabi and post-kharif periods for the first time on PM_2.5 levels across 140 stations over the IGP from 2015 to 2024. Results revealed that the fire activity during the post kharif season was ~ 4 and ~ 1.5 times higher in Punjab and Haryana, respectively but ~ 56.5% lower in Uttar Pradesh (UP) as compared to the post-rabi season, with a peak burning observed in November and May months, respectively. Despite negligible fires, Delhi recorded the highest PM_2.5 concentrations during post-rabi (85.95 µg/m³) and post-kharif (167.37 µg/m³) season, highlighting the role of regional pollution transport. The average PM_2.5 concentration during the post-rabi season was 48.76, 71.66, 85.95 and 66.00 µg/m³ in Punjab, Haryana, Delhi, and UP, with ~ 22%, 63%, 76% and 51% days exceedance to its standard limit, respectively. On the other hand, PM_2.5 was worsened during the post kharif, with an exceedance of ~ 90% in all states, except Punjab (~ 67% exceedance). While policies have reduced fire activities in Punjab and Haryana regions, their effectiveness is limited by the meteorological conditions and inadequate focus on post-rabi crop burning.