Remote policing of real-world emissions from on-road vehicles a must
Evidence from the new pilot study on remote sensing measurements of emissions from on-road vehicles in Delhi and the National Capital Region (NCR), underscores the importance of addressing real world driving emissions from vehicles.
New vehicles may get tested in the laboratory for compliance with mass emissions standards — currently the Bharat Stage VI standards — along with real world driving emissions regulations. But it is quite possible that the emission performance of these vehicles may deteriorate during their normal usage on the road. Unless that is tracked and controlled, investment in new vehicle technology and advanced emissions control systems may not help.
Vehicles have to remain low-emitting through their useful life on the road and not deviate from the expected performance level — irrespective of their age, usage pattern, and fuel types. It is the real-world emissions performance that decides the exposure level and the impact on air quality and public health.
This has emerged from the recently released results from the pilot remote sensing measurements of emissions from on-road vehicles organised jointly by the International Council on Clean Transportation (ICCT), Department of Transport, National Capital Territory of Delhi and Gurugram authorities. This provides deep insight into the emission profile of vehicles in the real world.
Remote sensing is a light source and a detector that is placed on the side of the road to transmit a laser beam to measure exhaust emissions remotely via spectroscopy as vehicles pass by and cross the light path. This can measure exhaust plume, and detect a range of pollutants including opacity, nitric oxide, carbon monoxide, hydrocarbons, and carbon monoxide. Many of these are not possible in the ongoing pollution under control (PUC) programme for on-road vehicles.
This pilot study has come at a time when a strong opportunity has emerged from the July 2024 directive of the Supreme Court, that in reference to its earlier directives of 2018 and 2019 and the recommendations from its former monitoring body Environment Pollution (Prevention and Control) Authority (EPCA) in 2018-19, have directed the Union Ministry of Road Transport and Highways (MoRTH) to implement a remote sensing device (RSD)-based programme and prioritise implementation in Delhi-NCR.
This Supreme Court directive had originally come in response to the recommendations of EPCA in 2018-19, that was triggered by an audit of the PUC programme in Delhi-NCR directed by the Supreme Court in 2017. Centre for Science and Environment (CSE) had participated in that process. The audit had exposed the weaknesses and ineffectiveness of the PUC programme, requiring reinvention and upgradation to a more advanced monitoring system.
Lessons from pilot RSD programme
This pilot project, that could generate 111,000 valid measurements mainly in Delhi with smaller sample size in Gurugram, has profiled emissions of wide-ranging exhaust emissions. This encompasses two- and three-wheelers (2Ws and 3Ws), private cars, taxis, light goods vehicles (LGVs), and buses.
The positive trends
The new evidence brings out the impact of ongoing measures to control vehicular pollution in the region, as well as the challenges with the transitional measures to improve emissions.
Leapfrog to BS VI emission standards has led to substantial reduction in tailpipe emissions: The RSD results validate the emissions benefits from the leapfrog across all vehicle types. Emissions levels from BS VI vehicles are much lower than the BSIV and older vehicles.
Substantial fleet renewal noted in the region: The measure to cap the age of vehicles at 10 years for diesel vehicles and 15 years for petrol vehicles, has led to a substantial turnaround. Almost 89 per cent of the surveyed vehicles in the region are certified to BS IV or BS VI standards, with a higher share of BS IV. Pre-BS IV vehicles are just about 11 per cent of the measured fleet. This shows early introduction of BS IV standards in 2010 has enabled substantial fleet renewal.
Curb on dieselisation in Delhi-NCR: Surgical measures have been taken since 1998 to curb dieselisation, and toxic diesel emissions. This includes fuel substitution measures like compressed natural gas (CNG) vehicles, and disincentives for diesel vehicles through air ambience cess on diesel fuel, environment compensation change on each daily truck entry, and environment pollution change on big diesel cars. As a result, the overall share of diesel vehicles has dropped substantially to 23 per cent in the on road vehicle mix. Petrol has the highest share of about 45 per cent, followed by CNG at 32 per cent.
Challenges of high real world emissions
BS VI vehicles may be the cleanest, but their real-world emissions are high: While overall emissions from the BS VI vehicles have reduced significantly, the real-world emissions have been found to be much higher than type-approval or certification limits. This is particularly so for NOX emissions across all vehicle types. For 3Ws, cars, taxis, LGVs, and buses, NOX emissions were 3.2 times, 2.0 times, 4.0 times, 4.9 times, 14.2 times, and 1.5 times higher, respectively, than their certification level in the laboratory.
Results from transitional strategy of CNG: The CNG programme has been an important transitional strategy since 1998 to curb toxic particulate emissions from diesel vehicles. However, the new results show that the real-world NOX emissions of the BS VI CNG fleet are high. For 3Ws, cars, taxis, LGVs, and buses, NOX emissions are 3.2 times, 2.0 times, 4.0 times, 4.9 times, 14.2 times, and 1.5 times higher, respectively, than type-approval limits.
While substantial particulate reduction benefits were possible from the CNG strategy by replacing polluting diesel technologies, inadequate focus on NOx control from vehicles have not led to adequate adoption of emissions control systems for gaseous emissions. But this only indicates the need to stay ahead of the pollution curve with newer strategies and further improvement in emissions control systems for all fuel types.
Particulate emissions from on-road diesel fleet remains a concern: Even though the share of diesel vehicles is comparatively smaller in the NCR fleet, the profiling of emissions of models according to the original equipment manufacturers (OEMs) show that PM emissions from diesel fleets of most OEMs were among the highest emitters.
Light goods vehicles and overall commercial vehicles with weaker emissions control systems are highest emitters: Overall, emissions from the commercial vehicle segment have been found to be very high. Particularly, light goods vehicles, dominated by the newer generation BS IV and BS VI LGVs, are the worst performers in terms of real-world NOX emissions. The study states that it has not been able to capture enough diesel LGVs for emissions analysis. But another study of ICCT that has tested a BS VI Class I diesel LGV using a portable emissions measurement system showed NOX emissions 6.2-7.9 times higher than the type-approval limits.
Focus on narrowing the gap between emissions certification level of new vehicles and on-road emissions performance: It may be noted that since the adoption of BS VI standards in 2020, considerable improvement has occurred in real world emissions regulations for new vehicles certification from 2023 onwards in India. On-road emissions testing with portable emissions monitors (PEMs) in real world driving conditions is needed for vehicle certification. In-service compliance requirements are also coming into place. The diesel gate that had shocked and rocked the world is the lasting reminder of why these checks are needed.
Currently, in the absence of data from PEMs testing or real-world emissions testing in India, this pilot RSD study has compared the RSD results with the type approval or vehicle certification testing done in the lab. Amit Bhatt and Anirudh Narla, the lead research team in ICCT, explain that this comparison is for representative purpose, and this does offer good insights on how high the real-world emissions can be as compared to lab testing conditions. In fact, London used similar findings which showed black diesel taxis emitting more than 10 times the type-approval limits to accelerate the zero emissions vehicle (ZEV) transition. Remote sensing covers a wide range of speed and acceleration conditions and the comparison is possible after averaging out the readings of hundreds/thousands of vehicles after ensuring a minimum sample size per vehicle type, fuel type and emission standard.
Going forward, more PEMs-based data will be available for comparison with RSD in India. In Europe, similar remote sensing studies could compare RSD data with the PEMs data showing a good agreement between PEMS and remote sensing. In Europe, hundreds of PEMS measurements from Euro 5 and Euro 6 vehicles were compared to thousands of remote sensing measurements.
It is explained that the Delhi pilot does not recommend taking any penal action based on this lab vs real-world comparison. It recommends developing 95th percentile limits — after the MoRTH carries out pilots. Only those exceeding these limits will be called for PUC retest or better chassis dynamometer testing.
Why will RSD help?
As opposed to PUC, the RSD programme can more efficiently identify high emitting vehicles to pull them over for proper checks and repair.
It can identify low emitting vehicles that don't have to unnecessarily go for physical emission inspection tests.
It will improve detection of tampering with emission control systems in vehicles. It will help characterise the emission factors of the on-road fleet to evaluate and provide feedback on the technology’s performance.
This will be more effective in addressing real world emissions performance of vehicles.
Way forward
Mandate time bound implementation of RSD monitoring: The Supreme Court directives on implementation of RSD in Delhi and NCR on a priority basis needs urgent compliance. To enable this, MORTH needs to notify Automotive India Standards 170 (AIS 170) rules with the threshold limits and guidance for cities. Improve the current draft to address measurement methods and adoption of threshold values for compliance and enforcement.
MORTH has sought a monitoring phase to generate vehicle emissions data using remote sensing to help define the accurate polluter thresholds. This must be expedited immediately.
Enable cities to implement the RSD programme: Several cities have included RSD in their respective clean air action plans but are unable to implement in the absence of notification from the MoRTH. In fact, Kolkata has been implementing this programme over a decade following a directive of the Calcutta High Court but it is challenging for them to expand this further without adequate legal compliance mechanism and certification systems.
Leverage the new automated testing centres to introduce advanced chassis dynamometer and short cycle-based emissions testing for confirmatory tests: Once the RSD programme rolls out and polluting vehicles are identified, they will require confirmatory tests. Currently, in the absence of an alternative, only PUC tests become the reference point. While that can be an intermediate strategy, more upgraded systems may be adopted as in Hong Kong.
Without RSD-based effective monitoring, it will be challenging to identify unfit and end-of-life vehicles for scrappage and fleet renewal: An analysis by CSE shows that the current data on VAHAN database is weak on identification of unfit and end-of-life vehicles. A stronger monitoring programme is needed to formally identify end-of-life vehicles for formal scrappage.
Accelerate zero tailpipe emissions: In view of the serious challenge of exposures from real world emissions from on-road vehicles, this new evidence builds the case for a quicker uptake of battery-operated vehicles with zero tailpipe emissions to curb toxic vehicular pollution.