NEW DELHI: A nearly two-degree dip early on Friday morning brought the minimum temperature downto 4.9 degrees Celsius, bringing Delhi its coldest dayyet this season.
The 4.9 degrees Celsius was four notches belownormal. It was 6.2 degrees Celsius on Thursday. Friday's maximum temperature was 25.4 degrees Celsius. On Thursday it was 24.1 degrees Celsius.
According to weather analysts, the reasons for the dip in mercury were clear skies that allowed the radiating heat to escape to the outer atmosphere early morning and at night and light north-westerly overnight winds.
The minimum temperature is recorded between 4 am and 5 am.
"The skies were clear on Friday and the city saw light north-westerly overnight winds leading to the drop. There are chances that the minimum temperature will remain below normal for the next few days. However, there is a western disturbance approaching the region, which could lead to rise in the maximum and minimum temperatures over the next few days. However, after December 17, the temperature will fall again," Kuldeep Srivastava, senior scientist with the India Meteorological department (IMD), said.
The city's air quality index continued to remain in the "very poor" range. The AQI on Friday was 323, against 320 a day earlier.
According to the air quality early warning system, the air is likely to be "very poor" on Saturday too.
"The air quality is likely to remain in the very poor category from 16.12.2023 to 18.12.2023," the IITM's air quality early warning system said. For the next six days, "the air quality is likely to remain in the poor to very poor category.... The predominant surface wind is likely to be from northwest/west direction in Delhi with a wind speed 4-8 kmph, partly cloudy sky becoming mainly clear towards the afternoon and mist/shallow fog in the morning on 16.12.2023," the air quality early warning system added.
The ventilation index is likely to be 2,800 m2/s on Saturday, 5,000 m2/s on Sunday and 7,500 m2/s on Monday. The ventilation index lower than 6,000 m2/s with average wind speed less than 10 kmph is unfavourable for dispersion of pollutants.
According to the IITM's decision support system, 14.7% of the city's total PM2.5 load was because of transport emissions, 6.2% for industries in and around Delhi and 36.9% because of other sources.
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