Effective from April 1, 2027, emission standards for BS6 vehicles – M1 and M2 categories – will be tested using the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) cycle. Category M1 and M2 vehicles include passenger cars and commercial passenger buses and vans with a gross weight of under 5 tonnes. The changes were notified via an amendment to the Central Motor Vehicles Rules, 1989, following draft norms issued by the Ministry of Road Transport and Highways on April 28, 2025.
- Change to apply to passenger cars and commercial buses and vans
- CAFE norms also currently use the MIDC cycle
- European Union adopted the WLTP cycle in 2018
- WLTP emission tests will be conducted on a chassis dynamometer
Move to WLTP will better reflect real-world emissions
The WLTP cycle is seen as a closer match to real-world driving than older lab-based test cycles. In India, both fuel efficiency and emissions are currently tested using the Modified Indian Driving Cycle (MIDC), a fixed speed-distance-time map. WLTP, adopted by the European Union in 2018, narrows the gap between laboratory results and on-road emissions of CO₂, nitrogen oxides and particulate matter.
As per the notification, WLTP-based emission standards will apply to all new vehicle models manufactured on or after April 1, 2027. Emission testing under WLTP will be carried out on a chassis dynamometer, in line with procedures specified in AIS-175, as amended from time to time.
India rolled out BS 6 emission norms nationwide in April 2020, significantly tightening emission standards. The shift to WLTP-based testing is expected to make emissions data more representative of real-world driving while keeping the existing BS 6 limits unchanged. CAFE norms also currently use the MIDC cycle. However, the Bureau of Energy Efficiency has proposed a move to WLTP from March 31, 2027, alongside the introduction of CAFE 3.
With inputs from Uday Singh.