The Central Pollution Control Board (CPCB) reports that farm fires contributed 3.5% to Delhi's PM 2.5 levels this year, a decrease from previous years. This estimate, based on the Indian Institute of Tropical Meteorology's Decision Support System (DSS), uses satellite data. However, some experts suggest this method may underestimate the impact, as farmers reportedly burn crop residue after 3 pm to evade satellite detection. CPCB officials maintain their methodology accounts for fires up to 5 pm, though independent analysts cite limitations in satellite data and emission inventories.