The national capital's air quality dropped to the season's worst on the morning after Diwali, but the situation was still better than the last three years, according to government agencies. According to the Central Pollution Control Board, the city's overall air quality index (AQI) stood at 345, the worst this season, at 10.30 am on Monday. The government's air quality monitor, SAFAR, had earlier predicted that Delhi's overall AQI would enter the "severe" category primarily due to firecracker emissions, unfavourable weather and a significant spike in stubble burning. After last year's Diwali, Delhi's AQI had crossed the 600-mark, which is 12 times the safe limit. The AQI post-Diwali was 367 in 2017 and 425 in 2016.