For the first time since Diwali, Delhi's air quality was registered in the 'poor' category on Thursday, an improvement from 'very poor' the day before, after rains lashed the city washing away the pollutants.
However, authorities warned that the condition may slip back to the "very poor" range from Saturday. The overall air quality index (AQI) in the national capital on Thursday was recorded at 213 which fall in the 'poor' category, according to data provided by the Central Pollution Control Board (CPCB).
Two areas of the city recorded 'very poor' air quality, 26 areas recorded 'poor' air quality while seven areas recorded 'moderate' air quality, it said.
On Thursday, the PM2.5 (particles in the air with a diameter of less than 2.5 micrometres) level was recorded at 105, while the PM10 (particles in the air with a diameter of less than 10 micrometres) was recorded at 191 in Delhi.
The EPCA has recommended curbs on non-CNG private vehicles to tackle rising air pollution, but experts say banning all private vehicles without a proper strategy and alternatives "is bound to create issues".
According to pollution watchdog the CPCB, 25 areas in the national capital registered poor air quality and 11 registered moderate air quality on Thursday.
The PM2.5 (particles in the air with a diameter of less than 2.5 micrometres) level was recorded at 95, while the PM10 (particles in the air with a diameter of less than 10 micrometres) was recorded at 177. 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'.
The Centre-run System of Air Quality and Weather Forecasting (SAFAR) said air quality improved significantly following sufficient rainfall on Wednesday night due to wash-away effect.
"Surface wind speed moderately increased but pollution level declined faster than expected. Still weather conditions are not completely favourable except sporadic rain. This implies that the air is lighter and free path increased to allow faster dispersion," it said.
"In addition to cleaning of air by rain, it also tends to suggest that accumulative emission loading is relatively less. Stubble fire is almost negligible.
The AQI is likely to remain in the 'poor' range on Friday but slip back to the 'very poor' range thereafter," SAFAR said.
Delhi's air quality has been oscillating between 'very poor' and 'severe' after Diwali due to explosion of fire crackers.
But after rains since Tuesday, the air quality has significantly improved, but fell in the 'poor' category. According to the Indian Institute of Tropical Meteorology, the PM2.5 concentration will improve in the next two days.
"The air quality is likely to improve in the next two days, but will remain in 'poor' and 'very poor' categories in Delhi NCR. Also, the impact of biomass burning in North West India is marginal over Delhi," it said.
