Delhi's overall air quality was in the usual 'very poor' category on Wednesday while in some areas of the city it was 'severe', with authorities mulling artificial rain by cloud seeding to wash away pollutants in the air.
Authorities said the 'very poor' air quality was due to low wind speed, which is unfavourable for dispersion of pollutants.
According to the System of Air Quality and Weather Forecasting (SAFAR) data, the overall air quality in the city was recorded at 358, which falls in the 'very poor' category.
At 396, the overall air quality of Ghaziabad was the worst in the National Capital Region (NCR), just points below severe category. Gurgaon, Faridabad, Noida and Greater Noida too recorded 'very poor' overall air quality.
On Wednesday, the PM2.5 (particles in the air with a diameter of less than 2.5 micrometres) level was recorded at 195, while the PM10 level was recorded at 326, the CPCB data said.
An AQI between 0 and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".
According to SAFAR, air quality in the national capital is expected to remain in the 'very poor' category for the next two to three days.
In the wake of rising air pollution in the city, authorities might induce artificial rain by cloud seeding to wash away the pollutants, although no exact date has been set for it.
"At present, the wind speed is unfavourable for dispersion but it may increase slightly to favour dispersion. Humidity is still high which is unfavourable. Fire counts from stubble burning declined and will have a marginal impact," the SAFAR said in a report.
A senior official said if the meteorological conditions are stable then cloud seeding for artificial rain would be done this week, otherwise, it would be done next week.
However, a senior environment ministry official said, "No exact date has been set for this. This is a possible solution. We will give more details about it."
The official also said the method of artificial rain is used only in 'severe plus' emergency situation.
Cloud seeding is the process of combining different kinds of chemical agents, including silver iodide, dry ice and even table salt, in clouds to thicken them and increase the chance of rainfall.
In 2016, the government tried to explore the possibility of cloud seeding for artificial rain but the plan never worked out.