Working Paper

Real-driving emissions from Bharat Stage VI (phase 1) passenger cars and a light commercial vehicle in India – PEMS testing

Real-driving emission (RDE) tests have been mandated for light-duty vehicles in India since April 2023 and are part of phase 2 of the Bharat Stage (BS) VI emission standards. RDE tests have proven critical for reducing real-world emissions in other regions and in India prior to April 2023, there was a monitoring phase for RDE during BS VI (phase 1), from April 2020 to March 2023. The ICCT contracted HORIBA India to conduct portable emissions measurement systems tests on four BS VI (phase 1) light-duty vehicles (three passenger cars and one light commercial vehicle) in 2022 in and around the city of Pune. While these phase 1 vehicles were not required to comply with the RDE regulation, the testing was to explore the real-world emissions performance of these vehicles and the effectiveness of the different emission control strategies deployed by vehicle manufacturers.

Two lean NOx trap (LNT) equipped test vehicles had NOx emissions higher than laboratory limits, whereas the emissions from the test vehicle with selective catalytic reduction (SCR) were well within the limits. Overall, results show that technologies for low emissions exist and can be optimized to achieve further emission reductions. These need to be widely implemented in India to achieve cleaner transportation. For example, the test vehicle which has a gasoline-direct injection engine and no gasoline particulate filter showed the highest particle number emissions among all the four test vehicles. Adopting the Euro 6e conformity factors in India could help ensure that vehicle emissions are measured and regulated more stringently, and lead to lower overall emissions and improved air quality.

Vehicle testing