Delhi saw a marginal respite in air quality on Monday as the 24-hour average Air Quality Index (AQI) improved to 244, in the poor' category, after lingering in the very poor' range a day earlier. Data from the Central Pollution Control Board's Sameer app showed that four stations recorded very poor' air quality, with Chandni Chowk logging the worst AQI at 321, while 25 stations remained in the poor' category and nine recorded moderate' air quality. According to the CPCB classification, an AQI between zero and 50 is considered good', 51 to 100 satisfactory', 101 to 200 moderate', 201 to 300 poor', 301 to 400 very poor' and 401 to 500 severe'. The Decision Support System indicated that Delhi's pollution load was led by transport at 13.7 per cent, followed by peripheral industries at 11.4 per cent, residential sources at 3.3 per cent, construction at 1.2 per cent and waste burning at one per cent. Among NCR districts, Jhajjar contributed the highest at 19.6 per cent, followed by Sonip