LUCKNOW, Dec. 23 -- After more than a week of relatively cleaner air, the city breathed toxins yet again on Monday when its overall air quality index (AQI) slipped to 222, according to Central Pollution Control Board (CPCB) data. Last time, the state capital recorded 'poor' air quality on December 14. Since then, improved wind movement and intermittent weather changes had kept AQI levels largely within the 'moderate' range. However, the relief proved short-lived. As per CPCB standards, an AQI between 201 and 300 is categorised as 'poor' and 301 to 400 as 'very poor'. Out of the six live monitoring stations, Talkatora Industrial Area was the worst-hit as it recorded an average AQI of 305. The area has consistently remained a pollution hotspot this month. Data show that out of the 22 days in December so far, the station has seen 12 'poor' and four 'very poor' days. Experts attributed Talkatora's persistently high pollution levels to the concentration of industrial units, heavy vehicular movement, and dense traffic corridors in the area, which together contributed to elevated particulate matter levels. Other monitoring stations also reported concerning figures. Kendriya Vidyalaya recorded an AQI of 292, followed by Lalbagh at 237, Gomti Nagar at 189, BR Ambedkar University at 161 and Kukrail Picnic Spot at 148. Experts warn that unless wind speed improves or emission sources are controlled, the city may continue to witness fluctuating air quality during the winter months, especially in industrial and high-traffic zones. Like Lucknow, several western Uttar Pradesh cities recorded elevated levels of AQI on Monday, with Noida faring worst at 366, the CPCB data showed. Noida was followed closely by Ghaziabad at 360, and then by Greater Noida at 332 and Muzaffarnagar at 313. Meerut (302), Bulandshahr (290), Khurja (261), Baghpat (266), Hapur (234) and Kanpur (209) were all placed in the 'poor' category. Arnav, a Class IX student who is visiting his relatives in Lucknow for the winter holidays, said the pollution has curtailed his outdoor activities. "We avoid going out because of the pollution. Most of our time is spent indoors, and we use an air purifier," he said. Several cities in central and eastern Uttar Pradesh, meanwhile, fared relatively better. While Agra (176), Moradabad (160), Prayagraj (121), Varanasi (130), Vrindavan (105) and Bareilly (126) recorded 'moderate' air quality, Firozabad (74), Gorakhpur (89) and Jhansi (55) recorded 'satisfactory' AQI....