The air quality in Delhi on Monday remained in the ''very poor'' category for the second consecutive day with the overall Air Quality Index (AQI) docking at 310, said Centre-run System of Air Quality and Weather Forecasting And Research (SAFAR).
An AQI between 0-50 is considered ''good'', 51-100 is ''satisfactory'', 101-200 ''moderate'', 201-300 ''poor'', 301-400 ''very poor'' and 401-500 is marked as ''severe/hazardous''.
The PM 2.5 and PM 10 levels in Delhi touched 206 and 214 respectively.
The SAFAR has advised the sensitive groups to avoid all physical activity outdoors and to keep medicine handy if they are asthmatic.
"It is advised to avoid outdoor activity at the early opening and after sunset times. Stop any activity level if you experience any unusual coughing, chest discomfort, wheezing, breathing difficulty," the weather body stated in its advisory.