Delhi and Gurugram have suffered the debilitating impacts of poor air quality for decades. The transport sector has been a major contributor to this form of air pollution. The study is part of the Real Urban Emissions (TRUE) Initiative, conducted in collaboration with authorities in Delhi and Gurugram, utilizing non-intrusive remote sensing technology to test the emissions of on-road vehicles
This new study, real-world motor vehicle exhaust emissions in Delhi and Gurugram using remote sensing, with technical analysis by the ICCT, offers insights into real-world tailpipe emissions from vehicles in Delhi and Gurugram and supports evidence-based policymaking to reduce vehicle pollution.
Exhaust emissions of nitrogen oxides (NOx), carbon monoxide (CO), hydrocarbons (HC), and ultraviolet (UV) smoke, a proxy for particulate matter, were measured from several vehicle types: two- and three-wheelers, private cars, taxis, light goods vehicles (LGV), and buses. The campaign captured over 100,000 valid measurements across 20 sites in Delhi and Gurugram and uncovered important patterns that can guide the development of targeted and effective policies to combat traffic-related pollution.
Key findings of the report include:
- Vehicles produced to the newest emissions standard – Bharat Stage (BS) VI – show significant improvements in tailpipe emissions across all pollutants and vehicle types measures. For example, real-world NOx emissions from private cars showed a reduction of 81 percent and buses nearly 95 percent as compared to BS IV.
- Many real-world emissions remain higher than set limits, particularly for NOx. High-use commercial vehicle emissions are much higher than private vehicles, for example, BS VI taxi and LGV fleets emit 2.4 and 5.0 times more NOx emissions than their private car counterparts.
- Compressed natural gas (CNG) vehicle fleets also showed high NOx emissions, challenging the narrative that CNG is a ‘clean’ alternative fuel. For example, Class II light goods vehicles are emitting up to 14.2 times their NOx lab limits and taxis 4.0 times.
“It is evident that real-world emissions from transport vehicles differ significantly from their laboratory values. For the first time in India, we have collected significant emissions data from motor vehicles on the road and it is crucial to remember that what impacts our air quality is not the laboratory emissions, but the pollutants released by these vehicles when they are in operation. Therefore, it’s time to reimagine our emissions testing regime and aggressively push for the adoption of zero-emission vehicles,” said Amit Bhatt, India Managing Director, ICCT.
Sheila Watson, FIA Foundation Deputy Director, added, “This important research clearly shows India and the rest of the world that compressed natural gas is not the clean alternative fuel which was promised. While Delhi battles with dirty air, a visible killer hanging over the city, TRUE has shown that this less visible but still deadly fuel is not the answer. For health and for the climate, the solutions to dirty air are to switch to walking, cycling, and shared electric mobility.”
The release of this report is timely given the recent directive of the Supreme Court of India to finalize the Automotive Industry Standard (AIS) 170 and implement remote sensing in the National Capital Region. AIS 170 will set the required technical parameters for remote sensing devices and provide authorities with the proper resources to measure vehicles exhaust in real-time.
“Remote sensing technology has the capacity to non-intrusively screen tailpipe emissions from vehicles on a mass scale under real-world operations and aid in the identification of highly polluting vehicles. It is encouraging to see the Supreme Court of India and the Ministry of Road Transport and Highways now deliberating to move forward with the implementation of this technology beginning with the National Capital Region, coinciding with the context of this study’s findings,” said Anirudh Narla, Researcher, ICCT India.
“Remote sensing as an on-road surveillance method can not only help identify and weed out the worst emitters, but also help understand emissions performance of different technologies and fuels. This shows that while the CNG transition has helped cut toxic particulate emissions from diesel vehicles during the early years, NOx emissions from on-road CNG vehicles without adequate controls can be high. This builds a case for the next big transition to electrification to make tailpipe emissions not cleaner but zero,” said Anumita Roychowdhury, Executive Director, Research and Advocacy, Centre for Science and Environment.