Winds sustain ‘moderate’ air days
Gurugram Air quality in the city remained stable on Thursday, settling at 112 (‘moderate’) on the Central Pollution Control Board’s (CPCB) daily air quality index (AQI) bulletin. This was marginally worse than the previous day’s AQI of 104, which saw Gurugram breathe its cleanest air since October 8.
The average concentration of finer particular matter with a diameter less than 2.5 micrometres (PM2.5) was 68ug/m3, six points above the safe limit of 60ug/m3. However, the lowest PM2.5 concentration was recorded at 22ug/m3.
Experts attributed the dispersal of pollutants to the easterly winds, which hit the city at a speed of 20 kilometres per hour. However, the wind speed is expected to slow down to 6kmph on Friday, as per the Early Air Quality Warning System for Delhi-NCR, which operates under the ministry of earth sciences.
Thursday also marked the coldest day of the season so far, with the maximum daytime temperature dipping to 22 degrees Celsius, as per data available with the India Meteorological Department (IMD). The dip is a steep one, from 26.6 degrees Celsius the previous day and marks a departure of four degrees Celsius from what is considered normal for this time of the year, said officials.
The minimum temperature on Thursday was 16.5 degrees Celsius and is expected to dip to 15 degrees Celsius, said experts.
Officials and experts attributed the prevailing chill to light showers and strong winds. The city, according to data available with the Palam observatory in Delhi, received 000.8mm of rainfall on Thursday. On Friday, there is a 20% chance of a thunderstorm, while light showers are expected to continue. The maximum humidity on Thursday was at 90%, which also helped settle suspended particulate pollutants.
However, it will be a few more weeks before the IMD officially declares the onset of winter. “Winter is defined by IMD as the season between January and February, and is declared toward the end of December or early in January,” said an IMD official.
According to the IMD’s forecast, temperatures are likely to touch maximum daytime temperature of 24 degrees Celsius over the next two days, before dipping again to 22 degrees Celsius, around December 4.
Thursday also marked the third consecutive day of ‘moderate’ air in Gurugram, a rarity for during November-end, when pollution levels usually start climbing toward their December peak. Moreover, this marks the second such stint of favourable air quality period this month, after pollution remained in the ‘moderate’ category for three days between November 17 and November 19.
“So far, there have been seven days of ‘moderate’ air in the city this month, which is unusual. If prevailing weather conditions continue, we may continue to have favourable air for another few days,” said Sachin Panwar, a city-based air quality scientist. According to the CPCB’s forecast, Gurugram’s daily average AQI over the next three days will not exceed 143 (‘moderate).