Delhi's air quality remained in the 'very poor' category with an AQI of 311, despite a marginal improvement on the second day of the new year. Dense fog across the national capital led to reduced visibility, causing significant delays for numerous flights. While most monitoring stations reported 'very poor' conditions, some areas like NSIT Dwarka registered 'severe' air quality. Airlines issued advisories warning passengers of potential disruptions due to the adverse weather.