New Delhi: The government has announced a major change in the way vehicle emissions will be tested in India. From April 2027, all passenger vehicles in the M1 and M2 categories will be checked using the Worldwide Harmonised Light-duty Vehicles Test Procedure (WLTP) under the Bharat Stage VI (BS-VI) norms. The decision has been notified through an amendment to the Central Motor Vehicles Rules, 1989. It was earlier released by the Ministry of Road Transport and Highways on April 28, 2025.
At present, India uses the Modified Indian Driving Cycle (MIDC) to measure fuel efficiency and emissions. However, the MIDC is based mainly on laboratory conditions and does not fully match real driving situations, says Autocar Pro. In the European Union the WLTP method has been used since 2018, and is considered more realistic because it measures vehicle performance in conditions closer to everyday road use.
What the new rule will cover
The new testing system will apply mainly to Category M1 and M2 vehicles. This includes passenger cars, sport utility vehicles, multi-purpose vehicles, and commercial passenger buses and vans with a gross vehicle weight of up to 5 tonnes. According to the notification, all new vehicle models made on or after April 1, 2027 will have to follow the WLTP-based emission testing. Existing models will also need to meet the same requirement from that date.
Under the revised rules, emission tests will be carried out on a chassis dynamometer following the procedures mentioned in AIS-175, as updated from time to time. The government has clarified that the current BS-VI emission limits will remain the same, but the method of checking them will change to WLTP so that results match real on-road behaviour more closely.
Link with fuel efficiency norms
India moved to BS-VI emission standards nationwide in April 2020, which was a big step toward reducing vehicle pollution. The latest decision is seen as the next stage in that process. Along with BS-VI, the Corporate Average Fuel Efficiency (CAFE) norms also depend on the MIDC test cycle at present. The Bureau of Energy Efficiency has suggested shifting CAFE testing to WLTP from March 31, 2027 with the start of CAFE-III.