Delhi's air quality improved slightly on Wednesday and was recorded in the "satisfactory" category as a result of increased wind speed that helped in the dispersion of pollutants, authorities said.
Delhi's overall Air Quality Index (AQI) was 99, the Central Pollution Control Board (CPCB) said.
An AQI between 100 and 200 comes under the "moderate" category, 201 and 300 is considered "poor", 301 and 400 "very poor", while an AQI between 401 and 500 is considered "severe".
In the National Capital Region, Ghaziabad, Gurgaon and Greater Noida recorded "satisfactory" air quality, while Faridabad witnessed "moderate" quality air, the CPCB said.
The overall PM2.5 levels -- fine particulate matters in the air with a diameter of less than 2.5 micrometers -- in Delhi was 51, while the PM10 level was 90, the Centre-run System of Air Quality and Weather Forecasting (SAFAR) said.
The SAFAR too said the overall air quality over Delhi was in the "satisfactory" category.
"Wind speed is favourable for the dispersion of pollutants. AQI is predicted to increase slightly to 'moderate' by tomorrow. The air quality will remain in 'satisfactory' to 'moderate' category in the next three days," the SAFAR said.
Delhi Air quality was recorded in the "moderate" category on Tuesday.