The air quality in Delhi has improved significantly over the weekend, after two days of light rains.
According to SAFAR (System of Air Quality and Weather Forecasting and Research), an app instituted by the Ministry of Earth Science, the air quality levels in Delhi improved to ‘good’ on Saturday morning, which continued during the course of the day.
SAFAR records 24-hour rolling averages of PM 10 and PM 2.5 and uses this data to estimate the Air Quality Index (AQI). PM10 and PM2.5 are ultra-fine particles that are the dominant pollutants in Delhi. The acceptable levels of PM10 and PM 2.5 are 100μg/m3 and 60μg/m3 respectively.
The larger particulate matter, measured by PM 10, docked at 83 μg/m3 in the morning, which dropped to 65 μg/m3 by 5 pm. PM 2.5, which measures the finer and more dangerous particulate matter, also hovered around 65 μg/m3 at 5 pm.
Experts say the rain in the national capital on Thursday and Friday was responsible for the improvement in air quality.
“Rain always has a washout effect on particulate matter. However, once the rains cease, as the sources of pollution are still continuous, we may see the levels rising again,” said Anumita Roychowdhury, executive director, Centre for Science and Environment.
With no rain being reported by IMD officials since Saturday morning, the air quality may further plummet. On Sunday, pollution levels in the city are expected to rise a little, though it will still be within the ‘good’ range. PM 10 and PM 2.5 levels are both expected to rise to 73 and 85 μg/m3 respectively by Sunday evening.
With winter almost over, and temperature is expected to rise, Roychowdhury also warns about other pollutants. “Gaseous pollutants like ozone, especially, will start posing a bigger threat,” she said.
With temperature dropping to 11.4°C and never rising above 23.6°C, Saturday was a cool day in the city. Sunday will be cooler, but sunny day in the national capital with temperature ranging between 9°C and 25°C, notches below the normal average temperature expected during this time of the year.
On Holi day, one may have to brace temperature as low as 9°C, so may be go easy on the pichkaris. However, you will be able to breathe some clean and fresh air.