Air better but may get worse in next few days

NEWDELHI: Delhi’s air quality continued to vacillate between ‘very poor’ and ‘poor’ levels.

On Saturday, the air improved because of strong winds but government agencies warned the quality could deteriorate over the next few days.

The air quality index (AQI) was 249 at 4 pm. It improved to 243 at 8 pm. On Friday, however, the AQI had shot up to 337. On a scale of 0 – 500, while an AQI value between 201 and 300 is considered to be poor, a value between 301 and 400 is considered to be very poor.

“The AQI has been sliding from ‘very poor’ to ‘poor’ and again going back to ‘very poor’ over the past few days. This is primarily because of the meteorological conditions — changing wind speed and moisture levels,” said an official of the Central Pollution Control Board.

As the wind speed picked up from Friday evening, the pollu- tants that had got trapped and accumulated in air were dispersed. The pollution levels dropped.

According to the India Meteorological Department’s regional weather forecasting centre, the wind speed shot up to 20km per hour during the day. Around 2:30 pm, there were gusts of wind blowing with a speed of nearly 36km per hour. Delhi usually needs a wind speed of 10km per hour to disperse its pollutants.

“The pollution level could rise again, as the wind speed is expected to drop from Saturday night,” said a scientist from Safar, a pollution forecasting wing under the union government.

By 5:30pm on Saturday, the wind speed had already dropped to around 4km per hour. The minimum te mperature is also expected to drop. While the minimum temperature on Saturday was recorded at 13.4 degrees Celsius, the day temperature on Saturday was recorded at 27.9 degrees Celsius, which was one degree above normal.