Bahadurgarh, with a 24-hour average Air Quality Index (AQI) of 400, emerged as the most polluted city in the country after Diwali night, followed by Charkhi Dadri with an AQI of 389, according to the Central Pollution Control Board (CPCB).The CPCB figures, based on the 24-hour average AQI recorded at 4 pm on November 9, covered the period from 4 pm on November 8 to 4 pm on November 9 across 285 cities.Khora in Uttar Pradesh was the third most polluted city with an AQI of 380, followed by Rohtak in Haryana (378) and Khairthal in Rajasthan (362).  Anpara in Uttar Pradesh ranked sixth with an AQI of 355.Faridabad, Panchgaon and Sri Ganganagar recorded an AQI of 350 each, while Kaithal stood at 347.Of the 10 most polluted cities in the country, six were in Haryana, two in Uttar Pradesh and two in Rajasthan, highlighting the concentration of poor air quality in the National Capital Region and adjoining areas.Gurugram ranked 11th with an AQI of 345, followed by Delhi at 344.Of the 30 cities in the ‘Very Poor’ category across the country, 11 were from Haryana. These included Bhiwani (AQI 345), Manesar (333), Ballabgarh (316) and Narnaul (305), among others. Another 10 cities in the state recorded AQI levels in the ‘Poor’ category.Interestingly, while two Haryana cities had slipped into the ‘Severe’ category after Diwali night in 2025, no city in the state entered this category this year.As per the CPCB classification, an AQI of 401-500 falls in the ‘Severe’ category, which affects even healthy people and seriously impacts those with existing diseases.An AQI between 301 and 400 is classified as ‘Very Poor’ and can cause respiratory illness on prolonged exposure. The ‘Poor’ category, with an AQI of 201-300, can cause breathing discomfort to most people on prolonged exposure.