Spike in Air Pollution, Cold Wave Conditions Likely Beginning Dec 29: IMD
Air pollution levels are likely to rise and “cold snap” to “severe cold snap” conditions are likely to set in in many parts of northwestern India, including Delhi, from December 29, the Meteorological Department of India.
Delhi posted an Air Quality Index (AQI) of 337 in the “very poor” category on Saturday.
Under the influence of an approaching Western disturbance, widespread snowfall is highly likely over Jammu, Kashmir, Ladakh, Gilgit, Baltistan, and Muzaffarabad; scattered snow likely over Himachal Pradesh, Uttarakhand; and light rain or thunderstorms are likely over northern parts of Punjab, Haryana and Chandigarh on Dec. 27 and 28, IMD said.
After the western disturbance recedes and under the influence of the consequent strengthening of the cold and dry winds from the northwest or north to lower levels, conditions from “cold wave” to “intense cold wave” are likely to reestablish. “in Punjab, Haryana, Chandigarh, Delhi, Rajasthan and West Uttar Pradesh from December 29.
“The impact of the western disturbance will occur mainly in Jammu and Kashmir and Himachal Pradesh, where moderate rain or snowfall is expected. In Delhi, we can expect cloud cover and traces of rain. After the WD passes, a cold snap is likely to set in for three to four days starting December 29. We already have very low minimum temperatures bordering on cold wave conditions, ”said Kuldeep Shrivastava, director of the regional weather forecast center.
The northern parts of Saurashtra, Kutch, and western Madhya Pradesh are also likely to experience cold wave conditions. Frost on the ground is likely to be found in isolated areas of Uttarakhand, Himachal Pradesh, Punjab, Haryana, Chandigarh, Delhi, Rajasthan, and western Madhya Pradesh between December 28 and 29.
“Cold day” conditions are also likely in Punjab, Haryana, Chandigarh and Delhi on December 28 and 29 and in northern Rajasthan on December 29 and 30. Dense to very dense fog is likely to occur in Punjab, Haryana, Chandigarh and Delhi on December 28 and 29 and 30.
According to IMD, a ‘cold day’ or ‘severe cold day’ is considered when the minimum temperature is below 10 degrees and the maximum temperature is 4.5 degrees C or 6.4 degrees C below normal. A cold snap occurs on the plains when the minimum temperature is 10 degrees Celsius or less, and is 4.5 notches less than normal for the season for two consecutive days.
On December 27, when the wind direction temporarily shifts to the east, the wind speed is likely to slow and cause pollution levels to rise. “We always see that during the transition of winds, air pollution levels increase, but afterwards the wind speed is likely to increase,” Shrivastava said.
According to the early warning system for air quality of the Ministry of Earth Sciences, the ventilation rate for Sunday is likely to be 3,500 m2 / s. The ventilation index is a function of the mixing height and the wind speed and defines the capacity of the atmosphere to disperse pollutants. A ventilation rate below 2,350 m2 / s is considered poor. Mixing height is the height at which the pollutants in the air mix.