Fog or Smog? Hazy Skies Predict Slow Arrival of Winter in North India Amid Rising Pollution
New Delhi – Northern India has been covered for days by a thick, gray layer of haze, prompting questions about whether this is the approach of winter fog or a growing sign of smog. The India Meteorological Department (IMD) said that a Western Disturbance active in the Himalayan region is largely responsible for this sudden haze. This disturbance has changed the wind directions and this pollution, which was earlier concentrated over Pakistan and Punjab, will drift over Delhi and surrounding areas and will have a highly affected air quality.
What's Causing the Haze?
According to the IMD, the Western Disturbance caused changes in the wind flow from the west side to the east side, bringing pollutants from the neighboring regions into Delhi. "Dust, smoke and slightly lower temperatures had all combined to provide favorable conditions for haze formation," it added while combining with moisture to create conditions of fog. This, scientifically speaking is known as "nucleation"-where the dust and smoke particles served as nuclei for the formation of water droplets, acting as a layer of haze.
Fog vs. Smog: What's the Difference?
Although fog and smog both create a hazy atmosphere, they are very different. While fog is composed of water suspended in the air from minute droplets, smog is a mix of smoke and pollution. Smog is more gray or brownish in color due to its contents compared to the white color of fog. It causes more fog when humidity increases and temperatures drop. Meanwhile, smog forms when pollution builds up under low temperatures in an urban area.
Weather Forecast for Delhi and Surrounding Areas Upcoming
With the cooler winds from the hills entering post-Western Disturbance, Delhi and its neighbourhood should witness a lowering of temperatures till November 18. Delhi's maximum temperature is likely to remain around 30°C while the minimum would hover around 17°C from November 14 to 16. By November 17, the maximum could dip to 31°C with a minimum at 16°C while lowering to 30°C and 15°C by November 18.
Cold Winds to Bring Cooler Temperatures
It is for the first time that snowfall was seen in the mountains on the eve of previous winters, and now it has started again. This means the colder weather will now reach Delhi. Western Disturbances bring rain and snow to the Himalayan region, which lowers the temperature across northern India. Temperatures may drop by mid-November in Delhi and its surrounding areas because winds carrying south cooler air have begun blowing. But because winds are moving relatively slowly, winter might take a little longer this time to reach.
Fog and smog would leave a dense merge over Delhi and surrounding areas during morning and evening hours from November 14 to 18. Though the days could remain hazy, clearer skies can be expected once the plains receive the colder winds from the Himalayas.
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