LUCKNOW, Dec. 22 -- 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 h...