An independent study conducted by environmental scientists in Delhi has revealed that the use of CNG has failed to bring down pollution levels. This is because the impact of CNG has been nullified by the increase in the number of private vehicles every year.
According to Arun Attri, professor in School of Environmental Sciences, Jawaharlal Nehru University (JNU), “Delhi has more than 2.5 million private vehicles. Most of these are two-wheelers that operate on two-stroke engines and account for over 60% of hydrocarbon and 50% of Carbon Monoxide emissions in the city. About 30% of the vehicles run on diesel which causes significant pollution.”
“Power plants, factories, and biomass burning contribute heavily to pollution, followed closely by emission from petrol vehicles. The adoption of CNG fuel largely in public transport reduced the environmental load. However, increase in the number of private vehicles has neutralised the effect,” he said.
Ambient aerosols also have a significant bearing, direct or indirect, in the state of air pollution in Delhi. It is accompanied by varied and complex contributing sources in urban/mega-cities. The researchers observed that the major cause for presence of pollutants like fine and coarse particulate matter is driven by Delhi’s proximity to the Thar Desert in Rajasthan, construction activities and wind-blown dust. The situation is worsened by combustion linked emissions from vehicles, thermal power plants and biomass burning that releases a huge amount of pollutants in the air including harmful gases like CO2, CO, NO2, So2, and particulate pollutants like PM10 (coarse) and PM2.5 (fine) aerosols.
The researchers observed that Delhi’s air pollution has increased steadily during the past four years with a rise of minimum 25% in respirable pollutants each year. Delhi’s Environment Minister Imran Hussain, last week, convened a meeting of stakeholder departments/agencies that were authorised by the National Green Tribunal for imposing fines on people who burn leaves, garbage, plastic, rubber etc in the open.
The minister said, “There is a need to take action against the violators in order to reduce air pollution by all the concerned agencies. A review meeting will be held in a week’s time for the same.”
Earlier this year, the World Health Organisation had ranked Delhi as the city with the most polluted air in the world. To understand the problem, a group of environmental scientists from the JNU’s School of Environmental Sciences, Central University of Jammu and Central University of Himachal Pradesh have been studying Delhi’s air pollution causes and levels for the past four years. The researchers analysed the levels and sources of respirable and coarser sized particulate aerosols present in the air and trends in pollutant levels.
The Delhi High Court in July had upheld the ban by the NGT on diesel vehicles operating as cabs in Delhi. Also vehicles older than 10 years are not allowed on Delhi’s roads. “A ban alone is not enough. It is a collective responsibility of the citizens to use mass transit as much as possible and resort to using more environment friendly fuels like CNG and biomass fuels. Delhi has more private cars registered than have Mumbai, Bangalore and Chennai combined. With such a high number, the citizens have to understand the severity of the pollution problem in Delhi,” Hussain added.