Delhi and surrounding areas experienced heavy smog this morning, with the air quality index (AQI) classified as “very poor.” On Diwali, the AQI was recorded at 328, despite anti-pollution measures. In Anand Vihar, one of the 40 monitoring stations, the AQI reached 419, placing it in the “severe” category. AQI levels from 0 to 50 are considered good.