Satellite and atmospheric models based quantification of crop burning contributions on air quality in parts of the Indo-Gangetic Plain

Stubbles are the crop residue of harvested rice and wheat crops that accumulate in large quantities across the Indo-Gangetic Plain (IGP). This study presents a novel integrated, multi-sensor (Sentinel 2 A, Sentinel 5P and VIIRS) and multi-models to quantify stubble burning and dispersion of atmospheric pollutants across IGP for both pre-monsoon (Kharif) and post-monsoon (Rabi) seasons. Sentinel-2 A burned area mapping (The Normalized Burn Ratio (NBR) index with Random Forest algorithm) is utilised to classify land use land cover and map burned areas. Study utilised VIIRS active fire products employing a Fire Radiative Power (FRP) threshold (> 5 MW), along with HYSPLIT and NAAPS modelling, to enhance detection accuracy and assess pollutant movement. The FRP threshold effectively filters low-intensity noise and ensures robust identification of significant stubble-burning events only. Sentinel-5P data were utilized to quantify the Absorbing Aerosol Index (AAI) and atmospheric pollutants (SO₂, NO₂, CO, HCHO, and O₃). The study sites chosen for research are Ajnala (Amritsar, Punjab), Panipat (Haryana), and Siddharth Nagar (Uttar Pradesh). Outcomes reveal that (i) Random Forest classification shows agriculture as the dominant land use (43 to 67%) overall, Panipat (43.18%), Ajnala (60.94%), and Sidharthnagar (66.44%), with the highest burned area in Ajnala (29.75%), followed by Sidharthnagar (15.52%) and Panipat (13.23%), as indicated by VIIRS FRP and Sentinel-2 A data. (ii) significant pollution during burning periods, with elevated AAI (up to 0.50), CO (> 0.04 mol/m²), HCHO (12.5 × 10⁻⁶ mol/m²), and NO₂ (> 6.5 × 10⁻⁵ mol/m²), indicating strong impacts of stubble burning. (iii) The HYSPLIT model indicated that smoke plumes travelled 200–300 km across the Indo-Gangetic Plain, significantly impacting regional air quality. Notably, AAI values over Delhi and its neighbouring regions were higher than other parts of the IGP, suggesting the influence of transported stubble-burning emissions from neighbouring states like Punjab and Haryana. This was further supported by the HYSPLIT model, which showed that north-westerly winds passing over the stubble-burning regions of Punjab and Haryana likely transported atmospheric pollutants towards Delhi and its surrounding regions. Overall, agricultural residue burning is a major driver of regional air pollution across study sites of the Indo-Gangetic Plain. These findings highlights the urgent need for policy interventions and sustainable residue management strategies to reduce stubble burning, mitigate air pollution and protect public health and environmental quality.