Chandigarh, Oct. 14 -- The air quality index (AQI) shot past 100 on Monday, taking the city's air quality from satisfactory to moderate, as per the Central Pollution Control Board (CPCB) data. This is the second time this season that the AQI has gone past 100. The previous such spike was seen on October 2, the night of Dussehra. As per the daily AQI bulletin released by CPCB, at 4 pm on Monday, the city's average AQI, based on readings from its three Continuous Ambient Air Quality Monitoring Stations (CAAQMS), stood at 107. On Sunday and Saturday, the readings were 86 and 83, respectively. By 8 pm, the AQI at Sector 53 CAAQMS reached 128, while Sector 25, on the outskirts, remained satisfactory at 82. AQI between 51-100 is considered satisfactory and can cause minor breathing discomfort to sensitive people. AQI between 101-200 is considered moderate and can cause breathing discomfort to the people with asthma, lung and heart diseases. Speaking about the AQI spike, UT chief conservator of forests, and director environment Saurabh Kumar said, "We will examine this particular uptick. The usual reasons for air pollution have to do with vehicle emissions. Other seasonal factors such as the changing weather also play a role." When the temperature drops, a phenomenon called temperature inversion prevents pollutants from getting scattered in the air and keeps them like a blanket over the city's air. MeT officials said that due to the recent temperature slide, the phenomena has started to take effect, while frequent rains were earlier keeping pollutants from building up in the city. While stubble burning also contributes to the rising AQI, Kumar said they haven't encountered any case of stubble burning in the tricity as of now. With Diwali scheduled for October 21, crackers are also likely to increase the AQI. Last Diwali, the AQI had gone up to 395 (very poor). The maximum temperature of the city rose from 31.7degC on Sunday to 32.6degC on Monday. The minimum rose from 17.3degC on Sunday to 17.7degC on Monday....