Rohtak/Karnal, Nov. 10 -- Air quality across Haryana collapsed to hazardous levels following Diwali celebrations, with 15 of 23 monitored cities hitting 'severe' air quality index (AQI) levels between 401 and 500 overnight, according to Central Pollution Control Board (CPCB) data. Several NCR and non-NCR cities recorded peak AQI readings of 500 between midnight and 2am due to widespread firecracker violation. The post-Diwali surge extended well beyond Delhi border towns. Cities across central and northern Haryana-including Karnal, Ambala, Kurukshetra, Kaithal, Sirsa, and Panipat-reported steep spikes in pollutant concentrations. Conditions slightly improved on Monday evening as the 4pm CPCB bulletin showed Bahadurgarh's AQI of 401, followed by Charkhi Dadri (388), Rohtak (385), Bhiwani (369), Kaithal (350), Faridabad (348), Sirsa (346), Manesar (339), Gurugram (332), Ambala (322), Ballabhgarh (319), and Sonepat (304)-all in the 'very poor' to 'severe' brackets. Other locations recorded 'poor' air quality: Narnaul (298), Dharuhera (286), Jind (289), Panipat (276), Hisar (270), Kurukshetra (224), and Yamunanagar (202). Not a single monitored city in the state met 'satisfactory' standards. Pre-Diwali baseline data showed rapid degradation within hours. Districts, including Kurukshetra, Karnal, Ambala, Panipat, Rohtak, Gurugram, Sonepat, and Dharuhera, spiked from 'poor' directly into 'severe' territory overnight. Despite administration orders restricting firecrackers to an 8pm to 10pm window, violations continued past midnight. Experts attributed the spike primarily to firecracker smoke, compounded by ongoing paddy stubble burning and stagnant atmospheric conditions that trapped pollutants near the surface. However, data shows that only 13 farm fire cases were registered last year on Diwali, which was celebrated on October 20. The latest report reveals that Kaithal district remains the biggest contributor in fire farm fires this season, reporting 34 cases on Sunday, bringing its total tally to 58 cases. So far, Karnal stands at fourth position with 15 cases, followed by Kurukshetra (13), Ambala (11), Fatehabad (10), Rohtak, Hansi and Yamunanagar (5), Sirsa and Sonepat (3), Panipat (2) and Panchkula (1). Officials said as many as 28 FIRs have been registered and a fine of Rs.2 lakh imposed in the state so far, while 13 red entries were also made in the farmers' revenue records. Karnal deputy director of agriculture Jaswinder Saini said after verification, four fresh cases were registered on Monday and a total of eight FIRs have been lodged so far against farmers for burning stubble. Health experts highlighted PM2.5 concentrations as the critical risk factor. These fine particulates penetrate deep into lung tissue and the bloodstream, elevating immediate and long-term risks of respiratory distress, cardiovascular events, asthma exacerbations, and stroke. Under CPCB standards, an AQI of 0-50 is rated good, 51-100 satisfactory, 101-200 moderate, 201-300 poor, 301-400 very poor, and 401-500 severe. At severe levels, air pollution poses health risks to individuals, while compounding dangers for those with pre-existing respiratory or cardiovascular conditions....