delhi

Updated: Jan 16, 2018 21:59 IST

Delhi’s air quality, which was hovering in the ‘very poor’ zone over the past few days, improved to poor category on Tuesday.

The Air Quality Index value dropped to 256 on Tuesday from 330 on Monday. On a scale of 0–500, an AQI value between 200 and 300 is considered ‘poor’. It is considered ‘very poor’, if the value stays between 300 and 400.

Scientists of the Central Pollution Control Board said that strong winds from the north and northwestern parts of India have managed to disperse the pollutants, thus improving the air quality.

“This is the third time in this month that air quality has improved to ‘poor’ levels. It is likely to improve further if the strong winds continue,” said D Saha, head of the air quality laboratory at CPCB.

January being one of the peak winter months the air quality usually remains in the ‘very poor’ zone on most of the days in the national capital.

While in January 2016, Delhi could enjoy just two days of ‘poor’ air quality, in January 2017 there were nine days when air quality was ‘poor’ and two days when the quality improved further to ‘moderate’.

RWFC scientists have forecasted that there could be moderate fog on Thursday and visibility could be reduced to around 300 – 500 metres. This, however, won’t affect flight schedules, MeT officials said.

On Tuesday while the minimum temperature was 9.1 degrees Celsius, two degrees above the climatic normal, the maximum temperature was 25.5 degrees Celsius, six degrees above the climatic normal.

“There won’t be any drastic drop in the mercury level over the next few days. This, however, doesn’t mean that winter is gone. If there is fresh snowfall in the hills, the chill would return to Delhi,” said a senior MeT official.

There is, however, a possibility that pollution levels could spike marginally on Thursday.

“The wind is now blowing at nearly 15 km / hour. But the speed could drop on Thursday and there would be increase in moisture levels too on Thursday,” said Kuldeep Srivastava, a senior scientist with the regional weather forecasting centre (RWFC).

Saha said that an increase in the moisture level and a low wind speed could result in spike in pollution levels as the pollutants won’t get dispersed easily.