India’s Automotive Research Association of India (ARAI) will shift to stricter Worldwide Harmonised Light Vehicles Test Procedure (WLTP) standards by April 2027. This move aims to fix the gap between claimed mileage and real-world fuel efficiency, which has widened due to the use of E20-blended fuel. The change will impact all new passenger and light commercial vehicles up to 3.5 tonnes.
The Automotive Research Association of India (ARAI) is planning a major shift in how vehicle fuel efficiency is tested in the country. Starting April 1, 2027, the industry will move from the current Modified Indian Driving Cycle (MIDC) to the Worldwide Harmonised Light Vehicles Test Procedure (WLTP). This transition is designed to provide consumers with more accurate mileage figures that better reflect actual road usage.
Why Mileage Discrepancies Are Rising
For years, vehicle owners have reported significant differences between the fuel efficiency numbers advertised by manufacturers and the actual mileage achieved in daily driving. This gap has become more noticeable following the industry's shift to E20-blended fuel, which is petrol mixed with 20% ethanol. E20 fuel inherently contains less energy than pure petrol, which can lead to a reduction in fuel efficiency of approximately 2% to 6%. Because current testing methods have not fully captured these variables, consumers have increasingly voiced frustration over lower-than-expected performance from their vehicles.
Stricter Testing Protocols
Under the new AIS 175 WLTP regulation, vehicle testing will become significantly more demanding. Instead of the shorter, controlled lab tests used today, new vehicles will undergo around 400 hours of testing in environments that mimic real-world driving. These protocols include aggressive acceleration, higher speeds, and dynamic braking to ensure that certification figures are closer to what a driver experiences on the road. To support this change, ARAI has already begun upgrading its testing infrastructure, including its 4x4 chassis dynamometers and automation systems.
Impact on Manufacturers and Investors
This regulatory update will impact all passenger vehicles and light commercial vehicles weighing up to 3.5 tonnes. For automakers, the transition may require adjustments to engine calibration and vehicle design to meet the more rigorous testing criteria while maintaining competitive performance metrics. Investors should monitor how different original equipment manufacturers (OEMs) manage this transition, as those with a strong focus on fuel efficiency may face more pressure to maintain their market positioning under the new, transparent testing regime.
While the goal is to improve consumer trust, the success of this implementation will depend on how efficiently companies update their testing workflows over the next several months. The market will also watch for any potential impact on production timelines or vehicle costs as companies upgrade their models to comply with the new global standards before the April 2027 deadline.