A layer of smog engulfed Delhi on Monday as the region's air quality deteriorated to 'very poor' category. As per CPCB, Delhi recorded AQI reading of 328 in the morning and the worst areas included Anand Vihar with an AQI of 357 and Ashok Vihar with 361. Gurugram and Noida also recorded high pollution levels at 195 and 267, respectively.