Noida slips back to ‘very-poor’ zone as mercury falls, Saturday, Sunday to be coldest of season so farUpdated: Nov 20, 2020, 23:15 IST
The air quality of Noida, Greater Noida and Ghaziabad continued its downward trend on Friday with Noida entering the “very poor” zone and the other two cities going deeper in the same zone after having slipped into it a day earlier.
Added to this, the India Meteorological Department (IMD) predicted that with Delhi expected to suffer a “cold wave” over the weekend, the three national capital region (NCR) cities will also experience some part of it. A cold wave is declared when the minimum temperature falls significantly from the normal minimum.
“The region is receiving north-westerly winds which is bringing some smoke from stubble burning from those parts of the country. On Friday morning till the afternoon, the region had wind with speed ranging between 18 to 20 kmph. But since the temperatures were low during the morning hours, so the ventilation would have been minimal, leading to spike in the air pollution,” said Kuldeep Srivastava, head, regional weather forecasting centre, India Meteorological Centre (IMD).
Low temperatures result in denser air making it difficult for wind to disperse pollutants.
On Friday, Delhi recorded its lowest minimum temperature for November since 2006 at 7.3 degrees Celsius, which was five notches below the season’s average and is also representable for the NCR.
“There could be some variation of two to three degrees in the average minimum temperature of Delhi-NCR and the actual temperature of Noida. But the next two days will see rise in chilly winds and a further temperature drop. This could also make the pollution dispersion a bit difficult,” said Srivastava.
According to the central pollution control board (CPCB), the air quality index (AQI) of Noida on Friday 306 or ‘very poor’ against 284 or ‘poor’ a day earlier. The AQI of Greater Noida was 314, same as a day earlier. The AQI of Ghaziabad was 325 against 305 a day earlier.
The AQI between 301 and 400 is considered ‘very-poor’ and between 201 and 300 is ‘poor’.
The pollution mass also worsened with PM2.5 for past 24-hours in Noida increasing to 173.92 microgrammes per cubic metres (µg/m³) against 144.85µg/m³ a day earlier. The PM2.5 for Greater Noida also worsened to 177.92µg/m³ on Friday against 161.22µg/m³ a day earlier.
According to the System of air quality and weather forecasting and research (SAFAR), the AQI may improve marginally due to wind over next two days.
“Energetic surface winds are forecasted for the next two days and likely to influence AQI positively. The AQI is likely to marginally improve and in the Very Poor to Poor category for the next two days. AQI is forecasted to marginally deteriorate and in the Very poor category on 23rd November,” said a statement by SAFAR on Monday.