The air quality in Kolkata and the surrounding areas was recorded in the "moderate" category on Kali Puja on Sunday, officials said. The air quality index or AQI was at 182 at Ballygunge, while it was at 111 in Bidhan Nagar at 11 pm, they said. At Jadavpur monitoring station, the AQI was recorded at 143 and at Rabindra Bharati it was measured at 173. An AQI between 0-50 is considered "good", 51-100 "satisfactory", 101-200 "moderate", 201-300 "poor", 301-400 "very poor", and 401-500 "severe". Above 500 is "severe-plus emergency" category.
At Rabindra Sarobar the AQI was measured at 147 and at Victoria Memorial it was 98, which is "satisfactory".
Air quality recorded at 'moderate' level causes breathing problem to those having asthma and other respiratory problem.
On last Kali Puja, the index breached the 250-mark. However, better vigilance and more awareness this time helped keep the AQI in the "moderate" level, officials said.
State pollution control board chief Kalyan Rudra said authorities will be on guard throughout the week to ensure better air quality.
However, environmentalist S M Ghosh said the readings at 11 pm were not reflective of the true and entire picture and there were areas, not covered by the air monitoring stations, where air polluting fireworks were burst and lit in the late evening hours.