New Delhi: The World Health Organisation (WHO) defines air pollution as, “a major environmental health problem affecting everyone. It occurs when the environment is contaminated by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.”
If the increasing levels of particulate matter in the air wasn't enough, the growing number of four and two-wheelers taking over Delhi roads has worsened matters further.
The latest economic survey of Delhi has shown that high vehicular density has led to a spike in nitrogen dioxide (NO2) levels, a major air pollutant, in the national capital.
Nitrogen dioxide is part of a group of gaseous air pollutants produced as a result of road traffic and other fossil fuel combustion processes.
Its presence in the air contributes to the formation and modification of other air pollutants, such as ozone and particulate matter, and to acid rain.
In 2015, the average level of NO2, a toxic byproduct of diesel combustion, was 73 micrograms per cubic metre (ug/m3), as against the permissible annual average of 40 ug/m3.
The rise in levels of NO2 was recorded along with a rise in the number of vehicles in the city. The national capital added around 8.78 lakh vehicles in 2015-16, the first year of the AAP government.
NO2 level rose sharply since 2011. The figures were 82, 77 and 79 ug/m3 in 2012, 2013 and 2014 respectively.
"In 2015, the average level was 73 micrograms per cubic metre. The minimum was recorded at Mandir Marg and the maximum at Civil Lines. The high levels may have been due to high vehicular density in the areas. At all stations, annual average exceeded the permissible standard of 40 ug/m3," the report stated.
At Civil Lines, a posh area where VIPs, including Lt Governor Anil Baijal and Chief Minister Arvind Kejriwal, stay, the levels of carbon monoxide and surface-level Ozone were recorded on the higher side as well.
"The number of vehicles registered in Delhi has increased from 31.64 lakh in 1999-2000 to 97.05 lakh in 2015-16. The highest percentage of increase was seen in taxis. This has automatically enhanced pollution levels of Delhi through emission. There were 88.27 lakh registered vehicles in 2014-15," the report said.
On Yamuna river, the report said the water quality downstream of Wazirabad barrage, after the Najafgarh drain meets it, was not meeting the desirable norms.
"The water quality monitoring results in Delhi stretch clearly indicates that the river water is grossly polluted," the report said.
(With PTI inputs)