Air quality in Delhi is expected to remain "poor" for a fourth straight day today, with the national capital likely to record an Air Quality Index of 256, up from 222 on Saturday and 208 on Friday. The AQI is likely to worsen to "very poor" by the third week of October, according to the centre-run System of Air Quality and Weather Forecasting and Research (SAFAR). Certain neighbourhoods in Delhi, such as Anand Vihar and Wazirpur, have already recorded AQIs of more 300, placing them in the "very poor" category.