New Delhi, Jan 14 : The Commission for Air Quality Management (CAQM) on Sunday invoked Graded Action Response Plan (GRAP)-III in the Delhi-NCR after the air quality dipped to severe levels, owing to unfavourable meteorological and climate conditions. 'CAQM Sub-Committee for operationalization of GRAP called on an emergency meeting today morning in view of sudden deterioration of air quality of Delhi-NCR from last evening,' said the CAQM on X. It said that the sub-committee decides to invoke eight point action plan as per Stage-III of revised GRAP in the entire NCR with immediate effect. In GRAP-III, restrictions on plying of BS III petrol and BS IV diesel LMVs (4 wheelers) in Delhi and in the districts of Gurugram, Faridabad, Ghaziabad and Gautam Budh Nagar is imposed. On Sunday, the air quality at Anand Vihar plummeted in the "severe" category with PM 2.5 and PM 10 crossing 500 while the NO2 reached 133 and CO at 132, both in the "moderate" category, as per the Central Pollution Control Board (CPCB) at 6 p.m. The AQI at ITO also remained in 'severe' category with PM 2.5 breaching the 500 mark and PM 10 at 480, or 'severe'. The CO was recorded at 110 or 'moderate'. The PM 2.5 at Punjabi Bagh also reached 477 while PM 10 was at 404, both in the 'severe' category. The air quality at Jahangirpuri air quality monitoring station also entered into 'severe' category with PM 2.5 at 462 and PM 10 455. The CO was also reached at 97 or 'satisfactory'. The PM 2.5 at Okhla Phase-II was recorded above 500 mark and PM 10 at 487 both in the 'severe' category. At Mundka the AQI remained in the 'very poor' category with PM 2.5 at 365 and PM 10 at 210 or 'very poor'. The 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". However, at Bawana, the air quality was in 'very poor' category with PM 2.5 at 342 and PM 10 at 196, or 'moderate'. The AQI monitoring station at Dwarka sector 8 recorded PM 2.5 at 470 and PM 10 was at 433, both in the 'severe' category. The AQI at the Indira Gandhi International (IGI) airport station plummeted with PM 10 at 469 and PM 2.5 was at 413, both in the 'severe' levels. /IANS