Government Notifies WLTP Cycle for BS-VI Emission Testing From April 2027

In a bid to tighten the way vehicle emissions are measured, the government has notified the use of the Worldwide Harmonised Light-duty Vehicles Test Procedure (WLTP) for testing emissions under the Bharat Stage VI norms for M1 and M2 categories from April 2027.

This has been notified through an amendment to the Central Motor Vehicles Rules, 1989. The draft norms were issued by the Ministry of Road Transport and Highways on April 28, 2025.

Under the amendment, emission standards for BS-VI vehicles will now be tested using the WLTP cycle, which is considered more representative of real-world driving conditions than older laboratory-based test cycles.

The Modified Indian Driving Cycle (MIDC) is currently the speed-distance-time ‘map’ used for testing both fuel efficiency and emissions norms in India. WLTP, which the European Union adopted in 2018, ensures that emissions of carbon dioxide, nitrogen oxides, and particulate matter from vehicles on the road more closely reflect results recorded in laboratory conditions.

The change will apply mainly to Category M1 and M2 vehicles, which will include passenger cars, sport utility vehicles, multi-purpose vehicles, and commercial passenger buses and vans under a GVW of 5 tons.

The notification specifies that the revised WLTP-based emission standards will be applicable to all new vehicle models manufactured on or after April 1, 2027, and to all existing models from that date onwards.

The government has also specified that emission tests under WLTP will be conducted on a chassis dynamometer, following procedures laid down in AIS-175, as amended from time to time.

India implemented BS-VI emission norms nationwide in April 2020, marking a major tightening of emission standards for vehicles. The move to WLTP-based testing is expected to make emission measurements more reflective of on-road driving conditions, while retaining the existing BS-VI emission limits.

Apart from BS-VI, CAFE norms also currently rely on the MIDC for testing. However, the Bureau of Energy Efficiency has proposed a transition from the current MIDC to the WLTP cycle from March 31, 2027, with the introduction of CAFE-III.