New Delhi, Dec 19 (UNI) Delhi woke up to a thick blanket of toxic smog as the air quality in national capital deteriorates and visibility dropping to less than 50 metres.
According to the India Meteorological Department (IMD), very dense fog enveloped airports across the city, with visibility dropping to zero at Safdarjung and 50 metres at Palam.
At 5.30 am, the weather department forecast very dense fog over all districts of Delhi for the next two to three hours. Visibility began dropping from 3 pm on Thursday; while it stood at 800 metres under clear, bright sunshine in the afternoon, it gradually deteriorated over the next 12 hours, reaching 50 metres by 2.30 am on Friday.
Experts attributed calmer westerly winds of 4-6 kmph for reduced visibility and worsening air quality,
At 7:05 a.m. on Friday, Delhi Air Quality Index (AQI) plunged to 387, degrading further from Thursday’s rolling average of 373, according to data from the Central Pollution Control Board (CPCB) at the Sameer app.
The Centre Pollution Control Board (CPCB) classifies air quality as ‘moderate’ when AQI is between 101-200, ‘poor’ between 201-300 and ‘very poor’ between 301-400. Above 400 mark, the AQI falls under the ‘severe’ category; however, for the implementation of emergent GRAP measures, AQI values of 450 are categorised as ‘severe plus’. AQI levels breaching 400 affect healthy people and seriously impact those with existing conditions.
Low temperatures, moisture and calmer surface winds entrap the pollutants near the ground, due to thermal inversion, a phenomenon common in winter months.
Experts said that winds are likely to improve on Friday, but a fresh, feeble western disturbance over the weekend could again deteriorate air quality as opposing wind currents weaken surface winds.
Among the 40 active pollution monitoring stations of Delhi, 17 recorded ‘severe’ air, while several other hovered near the 400 mark. At 7:05 am, R. K. Puram, a pollution hotspot in Delhi’s residential area fared among the worst affected region with AQI levels touching 441, nearing closer to the CPCB’s ‘severe plus’ category.
Apart from calmer winds, Delhi witnessed a significant drop in maximum temperature on Thursday. According to IMD, maximum temperatures during the past 24 hours over Delhi recorded a fall of 4-6°C, settling at 20.1°C, departing over 2°C from the normal for this time of the year. While the minimum for the city stood at 9°C, in the near normal range.
The weather department has forecast a partly cloudy sky for the next five days, with moderate to dense fog during the morning and hours on Friday, Sunday, and Monday. Shallow to moderate fog is likely for Delhi on Saturday, Tuesday, and Wednesday, IMD forecast.
