Safe to Drive on E20, But Non-Calibrated Cars Can See Mileage, Performance Drop: M&M

As India expands the rollout of 20% ethanol-blended petrol (E20), Mahindra & Mahindra has cautioned that while the blend is safe to use, it could reduce mileage and acceleration in non-compliant vehicles. Nalinikanth Gollagunta, CEO of Mahindra’s automotive division, said the company is preparing an advisory to address customer concerns, which will be issued over the next few days. 

Gollagunta stressed that while customers need not worry about safety or warranty, calibration remains critical to performance. Mahindra began calibrating its vehicles for E10 petrol from April 1, 2023, while models built before that date were designed for pure petrol and are not optimised for higher ethanol blends. From April 1, 2025, all new vehicles are calibrated to run on E20, he added.

“That’s the nuance to it. You’re safe to drive in whichever fuel–E10, E20 or pure petrol. But calibration is done for pure petrol. From April 1, 2023, calibration for E10 happened. Anything produced after April 1, 2025, is calibrated for E20 as well,” he said.

Gollagunta also underlined that recalibration of older models is not possible due to emission regulations. “If you bought a vehicle earlier, can I calibrate it again? That we are not allowed to do because there’s emission norms for which I can’t do a software update. It needs a software update to do a recalibration, which is not allowed once the vehicle is out in the field,” he said.

While stressing that vehicles manufactured before April 2023 can still safely use E20, he cautioned that owners may notice changes in performance. “You could see either an acceleration degradation or a fuel efficiency degradation. But it’s hard to put a number to it,” he said.

He further clarified that even for E20-compliant vehicles produced from April 2025 onwards, some performance drop is inevitable, though the gap will be narrower compared with older models. 

“If it’s an E20 compliant vehicle, 2025 model, then the mileage hit you are taking over there versus what you would take on a 2021 vehicle would be different,” he said.

The comments come amid growing customer concerns over the compatibility of older vehicles with the government’s ethanol-blending programme, introduced to curb fossil fuel imports and advance India’s climate goals. With E20 now rolled out nationwide and effectively the default fuel at pumps, many drivers have complained of reduced mileage, engine damage, and higher maintenance and replacement costs.

Earlier on Thursday, Union Road Transport and Highways Minister Nitin Gadkari strongly refuted concerns about the fuel, calling the backlash a “political campaign” aimed at targeting him personally. Addressing industry leaders at the SIAM convention, Gadkari said there was “no truth” to claims circulating on social media. He argued that the petroleum lobby was stoking fears to undermine the government’s ethanol programme.

“The concerned auto companies, ARAI and others submitted their findings. The Supreme Court also took their stand,” Gadkari said, insisting that E20 was both climate- and cost-friendly. He highlighted that India spends nearly ₹22 trillion annually on importing fossil fuels, which are more polluting than ethanol blends.