The air quality in Delhi and surrounding areas dipped to "severe" on Saturday as people defied a ban on lighting Diwali firecrackers in several areas, compounding the pollution caused by burning farm waste in neighbouring states. The city recorded an overall Air Quality Index or AQI of 414 on Saturday, which falls in the "severe" category. The 24-hour average AQI was 339 on Friday and 314 on Thursday.