Rain, strong winds clean up Delhi’s air

According to the India Meteorological Department (IMD) forecast, Delhi is expected to witness another spell of light rain on Tuesday evening, and added that the air quality is expected to remain between the poor and very poor categories for the next 48 hours

Light rain on Sunday evening and faster winds flushed out pollutants in Delhi’s air as the air quality index on Monday dropped two notches from severe (AQI 401-500) to poor (AQI 201-300) after staying in the severe zone for six consecutive days -- the longest spell of such bad this year.

IMD data showed that Delhi received 3.4mm of rainfall at Safdarjung in 24 hours ending 8.30am on Monday. The Ayanagar monitoring station recorded the most rain with the a recording of 5.6mm. (ANI)

The national capital recorded an AQI of 283, in the poor category, on Monday compared to Sunday’s 459 (severe) -- the worst since November 12, when the index had a reading of 471, according to the Central Pollution Control Board’s daily bulletin. Prolonged exposure to such air affects healthy people, and seriously impacts those with existing health conditions, according to the pollution watchdog.

According to the India Meteorological Department (IMD) forecast, Delhi is expected to witness another spell of light rain on Tuesday evening, and added that the air quality is expected to remain between the poor and very poor categories for the next 48 hours.

IMD added that temperatures are expected to drop Thursday onwards with a minimum of 6-7 degrees expected on both December 31 and January 1, officials said.

IMD data showed that Delhi received 3.4mm of rainfall at Safdarjung in 24 hours ending 8.30am on Monday. The Ayanagar monitoring station recorded the most rain with the a recording of 5.6mm.

Delhi recorded a maximum temperature of 22.6 degrees Celsius on Monday, which is two degrees above normal for this time of the year, and a minimum of 10.4 degrees Celsius, three notches above normal, IMD said. According to IMD forecast, the maximum and minimum temperature on Tuesday is expected to hover around 22 and 10 degrees Celsius respectively.

RK Jenamani, scientist at IMD, said north India is receiving light showers because to a western disturbance that will continue influencing Delhi till Tuesday. He added that the western disturbance is also keeping the temperatures higher than normal.

“The minimum will remain around 10 degrees till Wednesday. Cloudy skies under the influence of this fresh western disturbance are bringing light rain, but keeping the night time temperatures high. It will begin to dip only Thursday onwards, touching 8 degrees and around 6-7 degrees by January 1,” said Jenamani.

The maximum is also expected to drop to around 19 degrees Celsius by December 31, the IMD forecasts.

Experts said once temperatures begin to drop again, the air pollution may turn worse by the first week of January, adding that colder air will make dispersal of pollutants difficult.

“There is a strong correlation between low temperature and pollution. Temperatures are high again and the rain has washed away pollutants, but as it begins to dip again, we can expect severe air once again in the first week of January,” said Dipankar Saha, former head at CPCB’s air laboratory.

According to the System of Air Quality and Weather Forecasting And Research (Safar), a forecasting body under the Union government, wind speed is again dropping that could lead to a slight rise in pollution by Tuesday. “The AQI improved due to last night’s rain that cleared particulate matter. For December 27 and 28, winds are likely to blow at slower speed, reducing ventilation of pollutants. However, on December 29, an improvement is expected due to easterly winds that enhances ventilation of pollutants,” said Safar’s forecast on Monday.