Delhi pollution out of ‘severe’ zone as air quality improves, expect better days ahead

The Central Pollution Control Board data shows that the Air Quality Index which had shot up to 408 on Tuesday, had come down to 380 around 8am on Wednesday. The visibility, both in the city and at the airport, had also improved.

Delhi on Wednesday saw some relief from heavy fog even as the air quality was down to ’very poor’ levels from being ’severe’ on Tuesday.

India’s official pollution forecasting system SAFAR has said that the air quality is likely to improve further as level of particulate matter is expected to decline. (Sushil Kumar/HT PHOTO)

The average Air Quality Index of Delhi was recorded at 398, a marginal dip from Tuesday’s 408, which was in the ‘severe’ zone. The AQI is calculated on a scale of 0-500. An AQI between 0-50 is considered good, 51-100 satisfactory, 101-200 moderate, 201-300 poor, 301-400 very poor and 401-500 severe.

According to RK Jenamani, the director in-charge of the IGI airport meteorological unit, the fog situation improved on Wednesday after three days.

“From 4am-6am, the visibility went down to around 100-150m. It then improved. The runway visual range was above the minimum requirement for take-offs and landings. There is similar forecast for Thursday,” he said.

A Delhi International Airport Limited (DIAL) official said there was no impact on flight operations due to Delhi weather on Wednesday.

At the Safdarjung observatory, which is considered a representative of the entire city, at 4am visibility came down to 100m.

“In the morning hours, after 6am, it became 400m and later it was 1500m. This is because of good wind speed to the tune of 12-15km/hour throughout the day. On Thursday, there is a forecast of moderate fog with visibility expected to be 500m in the morning. It will further improve later in the day,” Kuldeep Srivastava, a senior Met department scientist, said.

In terms of temperature, the maximum on Wednesday was 18.4 degrees Celsius, a notch below normal, while the minimum was 7.4 degrees Celsius, which is normal for this time of the year.

According to the MeT department, the maximum and minimum temperatures would be around 20 and 6 degrees Celsius respectively on Thursday.

The good wind speed also helped improve the air quality. According to the Central Pollution Control Board’s (CPCB) real-time monitoring, at 7pm on Wednesday, the concentrations of PM2.5 and PM10 were 227.4ug/m3 and 374.3ug/m3 respectively. This is marginally better than Tuesday, when at 7 pm the concentrations of PM2.5 and PM10 were 271.8ug/m3 and 447.5ug/m3.

“Strong winds from the north and north-west are vital for improving Delhi’s air quality. They help to flush out the pollutants,” said Dipankar Saha, head of the air quality laboratory at CPCB.