Crop Residue Burning in North-Western India: Emission Estimation and Uncertainty Quantification

Air quality in India faces significant risk from agricultural residue burning, especially in Punjab and Haryana, which are pivotal to the world's second-largest agrarian economy. This study quantifies emissions from post-monsoon biomass burning (10 October–30 November 2022) in these states using VIIRS fire detection data and Sentinel-2-derived burnt areas. Ground validation via district-level surveys aligns with the findings of our study. Results show 51% of the total crop area was burned (14,700 km² in Punjab; 8,300 km² in Haryana), leading to substantial emissions of PM_2.5 (54.28 Gg; 7.94 Gg), CH₄ (25.63 Gg; 3.75 Gg), CO₂ (1,100.3 Gg; 195.7 Gg), NH₃ (0.83 Gg; 0.15 Gg), SO₂ (0.68 Gg; 0.12 Gg), and CO (62.1 Gg; 11.04 Gg). Emissions in Punjab are about 6.5 times higher than in Haryana attributable to greater burnt area (∼14,700 km²), higher crop yield, and elevated residue-to-crop ratios. Compared to VIIRS, Sentinel-2 data provides approximately 3.6 times higher emission estimates, reflecting improved burnt area detection. District-level emission variations underscore the influence of diverse farming practices, weather, and residue management. An uncertainty analysis, derived from multiple emissions estimates and methodologies, highlights regional disparities: SO₂ exhibits the highest uncertainty in both states with PM_2.5 and CO, respectively, showing the least. Understanding these emissions and uncertainties is vital for forecasting air pollution in downwind cities such as New Delhi and for formulating targeted mitigation strategies.