New Delhi, Dec 23 : Delhi continues to grapple with alarming levels of air pollution, reaching 'severe' conditions. In the morning, the air quality in the national capital on Thursday was categorised as 'very poor,' but as of afternoon, it has further declined to the 'severe' category. The Air Quality Index (AQI) scale categorises levels from 0 to 500, with Anand Vihar breaching the 'severe' threshold. The persistent issue of poor air quality poses serious health concerns for residents, necessitating urgent measures to address the environmental challenges in the national capital. At the Anand Vihar area, PM2.5 levels remained into the 'severe' category standing at 500 and PM10 reached 495, and CO plummeted to 108, classified as 'moderate," according to the Central Pollution Control Board (CPCB). 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'. The Bawana station recorded alarming PM2.5 at 450 and PM10 at 398, both in the 'severe' and 'very poor' category, respectively. Although CO levels were marked 'satisfactory' at 98. The Indira Gandhi International (IGI) Airport T3 witnessed PM2.5 levels at 411 and PM10 at 323, both again falling under the 'severe' and 'very poor' category. The CO level was recorded at 111, maintaining a 'moderate' rating. ITO's monitoring station reported PM2.5 at 500, categorised as 'severe,' while PM10 touched 458. CO levels were 'moderate' at 127, with NO2 at 49, falling into the 'good' category. At the New Moti Bagh station, the air quality was 'severe,' with PM2.5 at 465. Okhla Phase-II recorded severe PM2.5 and PM10 at 454 and 420, in order. /IANS