Strong winds, less stubble burning make city's air cleaner; AQI at 137

New Delhi: Delhi's air quality improved to be in the moderate category on Friday morning due to favourable wind speed and is likely to get even better, according to the India Meteorological Department.

The city's 24-hour average air quality index (AQI), which was 302 on Thursday, improved to 137 on Friday.

On Wednesday, the 24-hour AQI was 413, which falls in the "severe" category.

An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", between 301 and 400 "very poor", and 401 and 500 "severe".

Stronger winds and a drastic reduction in the contribution of stubble burning were two major reasons for cleaner skies over Delhi, according to experts.

V K Soni, the head of the IMD's environment research centre, said the wind speed remained favourable throughout the night, leading to a better than predicted situation.

Usually, winds remain calm at night. On Thursday night, favourable wind speed (8-12 kmph) led to better dispersion conditions, he said. The maximum wind speed was 18 kmph on Friday, the IMD said.

The central government's Air Quality Early Warning System for Delhi said the air quality is likely to remain in the satisfactory to moderate category on Saturday and in the moderate to poor category on Sunday.

The share of stubble burning in Delhi's pollution has also reduced significantly as the harvesting season has ended.

The contribution of stubble burning in neighbouring states to Delhi's PM2.5 levels was just 2 percent on Friday and 1 percent on Thursday, according to the Ministry of Earth Sciences' air quality monitor, SAFAR.

The minimum temperature was 10.2 degrees Celsius on Friday. The maximum temperature is likely to settle around 25 degrees Celsius, the weather department said.

Calm winds and low temperatures trap pollutants close to the ground, while favourable wind speed helps in their dispersion.

Meanwhile, stubble burning incidents saw a steep rise of more than 20 per cent this year in comparison to the last two years, a factor which plays a significant role in spiking pollution levels in the Delhi-NCR, K J Ramesh, member of the newly formed commission for air quality management, said on Friday.

Ramesh said the 'Air Quality Management in the National Capital Region and Adjoining Areas' has started discussions with stakeholders and he exuded confidence of coming up with an "acceptable and suitable solution" to combat air pollution by next year.