Vehicular emissions major cause of Delhi's winter pollution, says CSE

Vehicular emission is the top contributor to Delhi's pollution during winter season--more than stubble burning, road dust or bursting of fire crackers -- with over 50 per cent of pollution from local sources linked to city's fragmented transportation system, according to the Centre for Science and Environment (CSE).

An estimated 1.1 million vehicles enter and exit Delhi daily, further worsening the air quality.

The traffic caused from this vehicle influx intensifies pollution, particularly nitrogen oxides (NOx), which account for 81 per cent of NOx pollution in Delhi.

According to data presented by the CSE, local pollution sources in Delhi account for 30.34 per cent of the city's air pollution (50.1 per cent of which is contributed through transportation), while 34.97 per cent originates from the neighbouring NCR districts and 27.94 per cent from other areas. Stubble burning contributes only 8.19 per cent to Delhi's pollution levels.

These data points are based on the CSE's analysis from different bodies, including the IITM, TERI-ARAI, CPCB's real-time air quality data and traffic data from Google map, among others.

"The major reason behind the rising air pollution in Delhi is the state of transportation. Stubble burning, road dust and the bursting of firecrackers are concerning, but they are not as significant as this issue. We must not focus on assigning blame -- whether it's the Centre's responsibility or the states' or blaming farmers or firecrackers," CSE Director General Sunita Narain told a press conference.

"While farm fires and firecrackers do aggravate pollution during the winter due to adverse weather conditions, they are not the sole contributors. The top contributor is vehicular emissions and we need year-round efforts to address this problem. Implementing GRAP alone, as an emergency measure, will not be enough," she added.

The CSE highlighted the need for an integrated transportation system focused on improving public transport to address these issues.

Currently, public transport in Delhi is costly for the users, with around 50 per cent of public transport users spending 18 per cent of their annual income on transit, compared to 12 per cent for private vehicle owners. This cost difference is due to the higher journey times and frequent interchanges required for bus travel, leading to a total cost nearly double that of private transport, as per the presented data.

Despite the demand, Delhi's public transport system remains inadequate. Although the city has added buses, reaching 7,683 buses (including 1,970 electric buses) by July 2024, it still falls short of the Supreme Court's 1998 directive to deploy 10,000 buses.

Currently, Delhi operates about 45 buses per lakh population, below the Ministry of Housing and Urban Affairs' benchmark of 60 buses per lakh population. Bus breakdowns are also on the rise, with cases increasing from 781 in 2018-19 to 1,259 in 2022-23.

Bus ridership, despite increasing, remains 25 per cent lower than pre-pandemic levels for DTC buses and seven per cent lower for cluster buses.

Meanwhile, metro ridership has shown some recovery, though counting methods were revised in 2019-20 to reflect the number of corridors used instead of unique trips by commuters.

Data shows that during peak traffic hours (5 PM - 9 PM), when average traffic speed drops to 15 km/h, NO2 levels are 2.3 times higher than noon levels (12 PM - 4 PM) when traffic speed averages 21 km/h. These congestion-related emissions worsen air quality, especially during winter when inversion layers trap pollutants close to the ground.

To achieve its clean air targets, Delhi must reduce emissions by 62 per cent. However, urban sprawl has increased travel distances, while public transport usage continues to decline, with a 20 per cent drop in bus travel over the past decade.

The high cost of congestion affects Delhi's workforce, with unskilled workers losing an estimated Rs 7,500 to Rs 20,100 annually and skilled workers Rs 9,900 to Rs 26,600 due to traffic delays, amounting to 4 to 12 per cent of their income.

Parking demand also strains resources, consuming over 10 per cent of urbanized land, with space needed for new cars registered annually equal to 615 football fields.

Though the Graded Response Action Plan (GRAP) Stage II recommends increasing parking fees to discourage private vehicle use, experts say this would require a Parking Management Area Plan (PMAP) to be effective.