Delhi recorded its worst post-Diwali air quality in four years on Tuesday, with PM2.5 levels peaking at 675, officials said. They added that the 24-hour average AQI on Diwali reached 345, in "very poor" category, compared to previous years' readings of 330 (2024), 218 (2023), 312 (2022), and 382 (2021). BJP government blamed stubble burning in Punjab rather than firecrackers.