LUCKNOW, Dec. 8 -- Uttar Pradesh capital Lucknow woke up to a hazy Sunday as its air quality slipped back to the 'poor' category for the first time this December as the Central Pollution Control Board's (CPCB) 4 pm bulletin recorded an AQI of 208.

This marks a fresh deterioration after nearly two weeks of relatively cleaner air. The last time Lucknow officially reported 'poor' air was on November 25, when the Air Quality Index (AQI) had touched 219. The Central Pollution Control Board categorises AQI values between 201 and 300 as 'poor', 301-400 as 'very poor' and above 400 as 'severe'.

Officials say the deterioration in the city's air quality is linked to falling temperatures, reduced wind speed and increased particulate accumulation o...