New Delhi: Delhi was shrouded in a layer of smog on Thursday as its air quality deteriorated to the mid-range of the ‘very poor’ category, recording an air quality index (AQI) of 350 at 4 pm.The AQI spiked to 387 in the higher end of the ‘very poor’ range at 10 pm, the highest this season. A higher AQI than this was last recorded on Jan 19 when it touched 410 (‘severe’ category).At least 18 monitoring stations in the city had ‘severe’ air quality Thursday, according to Central Pollution Control Board (CPCB). IIT-Delhi was the most polluted area at 466, followed by Chandni Chowk at 463, on a scale of zero to 500.The air quality is likely to stay within the ‘very poor’ category for the next two days, according to Air Quality Early Warning System for Delhi.Burning of municipal, garden and plastic waste, paddy residue, wood and coal was the dominant source of pollution at 25.4% from 1 am to 9 am, according to Indian Institute of Tropical Meteorology. Secondary organic aerosols also accounted for 25.4% and vehicles for 17% of pollutants. At just over 7%, firecrackers continued to impact the city’s air quality well after Diwali.CPCB’s data shows that the air quality worsened steadily during the day. The AQI was at 323 at 8 am before rising to 378 at 8 pm. The winds slowed down to an average of less than 5 kmph during daytime, hampering the process of dispersion of pollutants.As haze blanketed Delhi, visibility dipped sharply. At Safdarjung, the city’s base station, visibility at 3.30 pm fell from 2,000 metres Wednesday to 800m at the same time Thursday. Palam also recorded a drop in visibility to 1,200m, from 2,500m the previous day.Experts said met conditions are likely to be adverse next week, which could lead to trapping of pollutants. Gufran Beig, founder of System of Air Quality and Weather Forecasting and Research and chair professor at National Institute of Advanced Studies, said temperatures are set to drop once the influence of a western disturbance passes. With no rain expected over the next few days, a likely rise in farm fire emissions is set to add heavily to Delhi’s pollution load.
