New Delhi: Delhi recorded its worst air quality of the season at 187 Sunday, slipping to the higher end of the ‘moderate’ category. However, at least 19 monitoring stations recorded a poor AQI during the day. Experts warn that winter conditions like slower winds will cause more polluted days.A higher AQI of 246 in the ‘poor’ category was last witnessed on July 24 due to transboundary dust from Iran, Afghanistan and Pakistan moving towards northwest India.At 4pm, the 24-hour average AQI stood at 187, down from a 10am peak of 196. According to Central Pollution Control Board (CPCB) data, Mundka was the city’s most polluted station at 273, followed by CRRI Mathura Road and Narela, both at 258.Some neighbouring cities recorded worse readings, with Noida’s AQI at 281, followed by Ghaziabad at 248, Greater Noida at 171 and Gurgaon at 166.Dipankar Saha, former head of CPCB’s air laboratory, said, “The total emission load of any defined area remains almost the same through the year, barring exceptions such as massive fire incidents, crop-residue burning, large-scale construction, dust storms and other such events. The air quality in a given area is also likely to remain similar if the meteorological conditions are the same. However, it varies seasonally, particularly with changes in wind speed and direction.” He added that the air quality worsened Sunday as emissions were unable to disperse effectively because of low wind speeds.Delhi’s air quality deteriorates from mid-Oct as winter conditions coincide with an increase in farm fires.Gufran Beig, founder of System of Air Quality and Weather Forecasting and Research (SAFAR) and chair professor at National Institute of Advanced Studies (NIAS), said, “The winter chill, along with favourable north-westerly winds, is gradually setting in, which can facilitate the intrusion of pollutants. MODIS satellite fire products may no longer be relevant, given the apparent shift in the timing of farm fires.”Delhi’s air quality will likely stay ‘moderate’ for two days before turning ‘poor’ over the next 10 days, according to Air Quality Early Warning System.CPCB classifies AQI 0-50 as ‘good’, 51-100 as ‘satisfactory’ and 101-200 as ‘moderate’, 201-300 as ‘poor’, 301-400 as ‘very poor’, 401-450 as ‘severe’, and 451 and above as ‘severe plus’.Meanwhile, four flying squad teams constituted by Commission for Air Quality Management (CAQM) inspected a total of 25 road stretches covering 35 kilometres of Inner and Outer Ring Road under PWD jurisdiction. During the inspection, 17 violations of high visible road dust and accumulation of Construction & Demolition (C&D) waste were reported. “The observations made during the inspection indicate the need for strict and effective implementation of prescribed road-cleaning, sweeping and dust mitigation measures by the road owning agencies,” said CAQM.
