The country's capital Delhi is witnessing stifling pollution. Swiss group IQAir ranks the world's most polluted countries and cities. The national capital's 24-hour Air Quality Index (AQI) score touched 418. With this, the pollution level came in the 'severe' category for the first time. The weather turned sweltering as temperatures and winds plunged, visibility dropped and at least eight flights were diverted from the city. Pakistan's Punjab province, which borders India, is grappling with toxic air. The government there has banned outdoor activities this month, and closed schools. And ordered some shops, markets, and malls to close early. The current dense fog reduces visibility to 50-200 meters (164-657). The India Meteorological Department has said that this fog is expected to continue in northwest India for the next 2-3 days. Delhi grapples with smog every winter. Every year there is a mixture of fog and smoke because the cold air traps the dust.

The average air quality index (AQI) in the national capital New Delhi was recorded at 430 on Thursday morning, which falls in the severe category. As of 7:15 am on Thursday, the average air quality index remained at 430 points. In Delhi NCR cities, Faridabad was at 284, Gurugram at 309, Ghaziabad at 375, Greater Noida at 320, and Noida at 367.

AQI level above 400 in these areas

The AQI level has gone above 400 in most areas of the capital Delhi, including 420 in Alipur, 473 in Anand Vihar, 474 in Ashok Vihar, 422 in Aya Nagar, 455 in Bawana, 407 in Chandni Chowk, 417 at Dr. Karni Singh Shooting Range, 458 in Dwarka Sector 8, 435 at IGI Airport, 434 in ITO, 471 in Jahangirpuri, 408 at Jawaharlal Nehru Stadium, 444 at Major Dhyanchand Stadium and 440 at Mandir Marg.

The AQI was recorded at 407 in Mundka, 457 in Najafgarh, 438 in Narela, 421 in North Campus DU, 425 in NSIT Dwarka, 440 in Okhla Phase 2, 472 in Patparganj, 459 in Punjabi Bagh, 404 in Pusa, 454 in RK Puram, 453 in Rohini, 427 in Shadipur, 438 in Siri Fort, 444 in Sonia Vihar, 468 in Sonia Vihar and 467 in Wazirpur.

Here AQI level is above 300

The AQI level remained above 300 and between 400 in five areas of Delhi, with DTU recording 398, Mathura Road 395, Dilshad Garden 385, Lodhi Road 370, and Sri Aurobindo Marg 345.

How much AQI and how is it considered

0 to 50 is classified as good,
51 to 100 as satisfactory,
101 to 200 as moderate,
201 to 300 as bad and 301 to 400 as very bad. 401 to 500 is classified as severe and AQI above 450 is classified as severe plus.