New Delhi, Nov 30 (PTI) Delhi logged just three "severe" air quality days in November this year, the lowest since 2015, when the Central Pollution Control Board started maintaining Air Quality Index data.The monthly average Air Quality Index (AQI) stood at 320, the second best after 2019 when it was 312.An AQI between 201 and 300 is considered "poor", 301 and 400 "very poor", and 401 and 500 "severe".Experts attributed the relatively better air quality to the dip in the share of stubble burning in Delhi"s pollution, moderately favourable meteorological conditions and proactive implementation of curbs on pollution-causing activities.Delhi had recorded 12 "severe" air quality days in November last year, nine in 2020, seven in 2019, five in 2018, seven in 2017, 10 in 2016 and six in 2015.The average AQI in November stood at 380 last year, 328 in 2020, 312 in 2019, 335 in 2018, 361 in 2017, 374 in 2016 and 358 in 2015.According to the Indian Agriculture Research Institute, Punjab, which accounts for the maximum number of cases of stubble burning every year, reported just 49,922 farm fires this season (September 15 to November 30) as against 71,304 last year and 83,002 in 2020.The agrarian state logged 50,738 incidents of stubble burning in 2019, 59,684 in 2018, 67,079 in 2017 and 1,02,379 in 2016.Delhi recorded "severe" air pollution on November 1, November 2 and November 4 due to stagnant winds and a surge in stubble burning.The share of stubble burning in Delhi"s pollution peaked at 34 per cent on November 3.Mahesh Palawat, vice president (meteorology and climate change), Skymet Weather, said the wind direction changed to westerly and southwesterly intermittently, reducing the share of stubble burning.Delhi also logged fewer episodes of smog in the absence of heavy moisture in the air.The city also recorded its warmest November in six years, with an average maximum temperature of 28.8 degrees Celsius, according to India Meteorological Department (IMD) data.The mean maximum temperature for the month was 28.2 degrees Celsius. PTI GVS DIV DIV