The air quality in the Capital kept deteriorating throughout Saturday due to low wind speed since Friday. Forecast suggests a similar level of pollution on Sunday too.
The air quality index (AQI) was recorded at 401 –- “severe” category –- at 11am on Saturday, worsening to 416 by 2pm, and the 24-hour average AQI at 4pm was logged at 431, according to data from the Central Pollution Control Board (CPCB). The 10pm reading was recorded at 457 (severe+). On Friday, the 24-hour average AQI was 349 (very poor).
Meanwhile, 31 out of 39 active air quality monitoring stations of Delhi recorded an AQI above 400 on Saturday, which marks the fourth “severe” day of the year in the Capital. Before this, Delhi recorded a streak of “severe” air days from November 11-13.
Mahesh Palawat, vice president at Skymet, said, “The wind speed has been very low since Friday, leading to a spike in pollution levels. Due to the western disturbance, the AQI might remain in this range on Sunday as well. Wind speed might pick up from Monday again, bringing some respite.”
Forecasts by the Air Quality Early Warning System for Delhi (AQEWS) suggest the air quality is expected to be in “severe” category on Sunday and “very poor” on Monday. Weather experts said slight improvement in AQI is likely from December 15 onwards, as wind speeds are expected to increase once the western disturbance moves away.
“The air quality is likely to be in the ‘severe’ category on Sunday. The air quality is likely to be in the ‘very poor’ category on Monday and Tuesday. The outlook for the subsequent six days is that the air quality is likely to be in the ‘very poor’ category,” the AQEWS bulletin stated on Saturday evening.
The Capital also saw shallow fog early morning on Saturday, while the later half of the day saw a blanket of haze. According to data from the India Meteorological department (IMD), the visibility remained around 500 metre to 700 metre around 7.30am to 8am. This later improved to 1,300 metre during the day.
“In the evening hours, the horizontal visibility remained 1,100 m. However, an upper haze persisted in the evening, which was due to cloudiness, as well as influence of some easterlies which are bringing humidity to the city’s air,” said Mahesh Palawat.
IMD classifies it as a shallow fog when visibility is between 500m and 1,000m, moderate when it is between 200m and 500m, dense fog when visibility ranges from 50m to 200m, and very dense fog when visibility falls below 50m.
Meanwhile, the western disturbance might also lead to a rise in temperature. The minimum temperature was recorded at 8 degrees Celsius (°C), 0.6°C below the normal and the same as a day before. The maximum temperature, meanwhile, was recorded at 25.5°C.
“Minimum temperatures are likely to rise by about 2-3°C in the next couple of days and fall by 1-2°C thereafter. As a result, minimum temperatures are likely to be above normal (1.6 to 3.0°C) on Sunday and normal (-1.5 to 1.5°C) thereafter,” said an IMD official.
The official added, “Partly cloudy skies are expected to persist for the next couple of days. A moderate fog is expected to be observed in most places on Sunday.”
According to IMD forecasts, the minimum and maximum temperature are expected to be around 9-11°C and 23-25°C, respectively, on Sunday.