It’s become an annual ritual, scanning air quality reports for this time of year in Delhi and the National Capital Region (NCR). This year is, if anything, worse than ever. The website aqi.in shows the numbers for New Delhi as 476 at 10.29 am on December 15. The Air Quality Index (AQI) is a measure of the pollutants present in a typical sample of air. On the AQI scale, a reading of 0-50 is good, anything above 300 is “hazardous”. So the stark number, 476, tells its own tale.