Weather takes wind out of odd-even sails

New Delhi: It was a smoggy day for Delhi with visibility falling to 1,200m at the IGI Airport on Tuesday morning from 4,000m recorded a day before. Met officials said this was a result of weakening of winds, which could throw up some disappointing results for the odd-even scheme. A senior Met official said that Tuesday’s smog and haze were the worst the city has seen since March 1.“Besides odd-even restrictions, wind as a single meteorological parameter has a dominant role to play in dispersing or accumulating pollutants. There was a sudden calming of winds around 8.30pm on Monday to 3-4 knots, which in meteorological terms is calm, and visibility came down as a result of that. This may be because of dust accumulation caused by roadside sweeping, construction work or dust coming from other states,” said R K Jenamani, director in-charge, IGI Met.
“Levels of PM 10 and PM 2.5 might be higher on Tuesday because of this dust accumulation. Therefore, despite a reduction in vehicular related emission because of odd-even, wind-related dispersal of dust and emissions has been negligible.”
Sources said that visibility over the IGI Airport had been unusually good since March 8, wavering between 2,000m and 6,000m. In this period, there were consistent winds and two active western disturbances affecting the plains of northwest India. “Even till April 18, winds were consistent over the region and it was highly gusty from April 11 to 17 when speeds often reached 35-45kmph in the afternoon. Visibility was between 3,000m and 5,000m during this period,” said Jenamani.
The weakening of winds is a result of a western disturbance that is affecting J&K. The WD was also responsible for the cloud cover the city witnessed on Tuesday. The day’s maximum temperature was 40.6 degrees Celsius, four degrees above normal while the minimum was 26 degrees Celsius, four degrees above normal. “There will be a fall of 1-2 degrees in the maximum temperatures over the plains of northwest India over the next two days. The city will witness a partly cloudy sky till April 21. A dust haze is likely to persist,” said a Met official.