The national capital, routinely suffering from the toxic air caused by coal burning and vehicular exhaust, witnessed improvement in air quality on Thursday. According to the System of Air Quality and Weather Forecasting and Research (SAFAR), the overall Air Quality Index (AQI) of New Delhi recorded at 342 at around 9:09 am as compared to 419 on the previous day. “It is expected to be a mainly clear sky throughout the day,” an India Meteorological Department (IMD) official said.