New Delhi, Oct 21 : The air quality in the national capital dipped to "poor" quality as the overall Air Quality Index (AQI) of the city reached 266 on Saturday evening, according to the System of Air Quality and Weather Forecasting And Research (SAFAR). The AQI at Dhirpur entered into "severe" category with PM 2.5 at 342, under "very poor" category. Experts said that the air quality may also remain in a very poor category on Monday. AQI between zero and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and 401 and 500 'severe'. In Pusa, the AQI recorded PM 2.5 at 200 or "very poor" category. At Lodhi Road, the Air Quality Index with PM 2.5 concentration was at 173 under the "moderate" category and the PM 10 stood at 135, which is also under the moderate category. At IIT Delhi station the PM 2.5 was at 228 or "poor" category while the PM 10 reached 134 or "moderate" category. The Air Quality Index at the city's Mathura Road was under "moderate" category with PM 2.5 at 162 and PM 10 concentration at 132. According to the forecast from the SAFAR, the air quality of the city will deteriorate further under "poor" category with PM 2.5 reaching 297 and the PM 10 concentration at 161 under "moderate" category on Sunday. The Air Quality Index of Delhi's neighbouring cities of Noida stood at 290 and the PM 10 concentration at 258, both under "poor" category, while Gurugram's AQI was reported at 152 and the PM 10 concentration at 126 or "moderate". /IANS