Unfavourable meteorological conditions that slowed down dispersion of pollutants kept Delhi's air quality in the 'very poor' category for the third consecutive day Wednesday as a thick haze engulfed the city, authorities said.
The Central Pollution Control Board (CPCB) has come out with a list of nearly six lakh diesel and petrol vehicles that are over 10-years-old and will not be allowed to ply in Haryana.
The lists gives details of the registration mark series, name of the authority and registration numbers of these vehicles plying in Haryana, including NCR cities of Gurgaon, Sonipat and Bahadurgarh.
As many as 2,87,613 petrol vehicles that were older than 15 years have been listed while 3,07,453 diesel vehicles more than 10-years-old have also been named, the CPCB said on its website.
The overall air quality index (AQI) of Delhi was recorded at 323, according to Central Pollution Control Board (CPCB) data.
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 CPCB said 25 areas of Delhi recorded 'very poor' air quality while 11 areas recorded 'poor' air quality.
The level of PM2.5 -- particles in the air with a diameter of less than 2.5 micrometres -- was recorded at 179 and the PM10 level was recorded at 338, it said.
In NCR, Ghaziabad, Faridabad and Noida recorded 'very poor' air quality while Gurgaon fell into the 'poor' category, the CPCB data showed.
According to the Indian Institute of Tropical Meteorology, a haze has engulfed Delhi and the wind speed and ventilation index are "extremely unfavourable" for dispersion of pollutants.
Ventilation index determines how fast pollutants can get dispersed.
The ventilation index of around 6,000 sqm/second gets rid of pollutants, but it came down to 1,500 sqm/second on Wednesday in the city.
According to the Centre-run System of Air Quality and Weather Forecasting (SAFAR), the air quality is 'very poor' and likely to improve due to slight increase in wind speed but will remain 'very poor' for the next two days and then increase.
"Due to cold front up in the north, the wind speed has increased so a decline (in pollution) is expected. However, at the time of withdrawal after two to three days, a lot of moisture may enter Delhi which is not favourable for the air quality. The contribution from stubble biomass is nil," the SAFAR said.
The CPCB came out with a list of nearly six lakh diesel and petrol vehicles that are over 10-years-old and will not be allowed to ply in Haryana.
In October, the Transport department issued a notice warning that petrol vehicles that are 15-year-old and 10-year-old diesel vehicles plying on the city roads in violation of the Supreme Court and the National Green Tribunal (NGT) orders will be impounded.
In its 2015 order, the NGT had banned the plying of petrol vehicles older than 15 years and diesel vehicles older than 10 years in the national capital region (NCR).
It also banned the parking of 15-year-old vehicles in any public area. The Supreme Court endorsed the NGT order and directed that such vehicles be impounded.
Earlier, the CPCB has put a list of 3,30,947 diesel vehicles comprising buses, cars, motorcycles and even ambulances which were more than 10-years-old in Delhi that would not be allowed to ply.
The pollution watchdog also named 36,73,147 petrol vehicles that were older than 15 years old.
Delhi NCR has been battling alarming levels of pollution for over a month, prompting authorities to take a number of steps to combat pollution.
On Wednesday, the overall air quality index of Delhi was recorded at 323, the CPCB said.
The Supreme Court-appointed Environment Pollution Control Board had time and again reiterated the need to combat pollution caused by petrol and diesel vehicles which causes 40 per cent of pollution in Delhi NCR.