A statue of Mahatma Gandhi is seen in the vicinity of the Parliament House on the first day of Winter Session, in New Delhi (PTI)
A statue of Mahatma Gandhi is seen in the vicinity of the Parliament House on the first day of Winter Session, in New Delhi (PTI)

Clear skies bring cheer in Delhi, but air quality likely to worsen from Tuesday

  • As the wind calms, the air quality index (AQI) will deteriorate from ‘poor’ category (200-300) to ‘very poor’ (300-400) by Tuesday
  • The toxic haze had given way to bright sunlight over the weekend as air quality hovered over ‘moderate’ to ‘poor’ levels

NEW DELHI : Prevailing winds may have reduced the toxic haze engulfing the National Capital Region (NCR), but the relief may be short-lived as the air quality is likely to start worsening Tuesday onwards.

According to the government’s air quality monitoring service- SAFAR- the System of Air Quality and Weather Forecasting and Research, the moderate surface and boundary layer winds will continue to disperse pollutants till late evening, but they will begin to slow down Tuesday onwards.

As the wind calms, the air quality index (AQI) will deteriorate from ‘poor’ category (200-300) to ‘very poor’ (300-400) by Tuesday and subsequently worsen to ‘severe’ (400-500) on November 20-21.

“The Air quality is most likely to quickly touch ‘Severe’ levels back again on November 21, as the pollutant accumulation continues to increase," stated SAFAR, maintained by scientists at the Indian Institute of Tropical Meteorology (IITM), Pune.

The toxic haze had given way to bright sunlight over the weekend as air quality hovered over ‘moderate’ to ‘poor’ levels across most places in the National Capital Region (NCR). The situation continued on Monday, with prevailing winds preventing the toxic pollutants from choking the capital. It was only favourable weather conditions associated with a moving weather system, a western disturbance which brought rainfall over upper Himalayan region, which enabled a better air quality, otherwise the emissions from regular sources had continued.

On Monday, the AQI was recorded at ‘215’ for Delhi, which falls in the poor category, ‘209’ for Gurugram and ‘256’ for Noida. The concentration of PM2.5 - one of the most damaging pollutants in the air dropped to as low as ‘95’ microgram per cubic meter.

According to scientists, another factor that could play spoilsport to Delhi’s blue skies is the change in the direction of winds carrying the biomass plume from neighbouring states to north-west. This would lead to an increase in effective fire counts, and the intrusion of the biomass plume into Delhi.

The contribution of stubble burning to Delhi’s pollution which had come down to 3% last week, may start rising and is estimated to be 13% on Tuesday. As per NASA satellite images, the fire counts are not restricted to Punjab and Haryana, but are also being reported from Uttar Pradesh, Madhya Pradesh and Chhattisgarh.

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