One in two petrol vehicles sold before 2023 seeing mileage drop with E20: Survey

Half of petrol vehicle owners with a vehicle purchased 2022 or prior confirm experiencing lower mileage post E20 petrol mandate in 2025, according to a survey by LocalCircles.

The study shows that 1 in 2 petrol vehicle owners with a vehicle that was purchased in 2022 or earlier say their vehicle’s fuel efficiency/mileage has reduced in the last 9 months.

Similarly, 29% of owners of petrol vehicles (purchased in 2022 or prior) confirm experiencing unusual levels of wear & tear, or need for repair in the last 9 months with regards to engine, fuel line, tank, carburettor, etc, the survey notes.

The survey received over 50,000 responses from owners of petrol vehicles (2022 or prior models) located across 301 districts of India. 45% of respondents were from tier 1, 29% from tier 2 and 26% respondents were from tier 3, 4 & 5 districts.

While official estimates suggest that E20 petrol may reduce mileage by around 1–6%, but many users claim that real-world losses are higher, particularly in older vehicles operating under congested urban driving conditions, says LocalCircles.

“For middle-class households already facing rising living costs, even modest reductions in mileage translate into noticeably higher monthly fuel expenses,” it adds.

With E20 now effectively serving as the default petrol grade in most parts of the country, owners of older vehicles have few other fuel options. While some premium low-ethanol petrol variants are still sold for select high-end cars, their significantly higher cost puts them out of reach for most everyday consumers.

According to the survey, vehicle owners have frequently reported issues such as faster engine overheating, rough idling, difficulty during cold starts, higher vibrations, reduced acceleration, and a noticeable drop in fuel efficiency. Complaints about excessive engine heating have surged on social media during peak summer months, further amplifying consumer anxiety.

Industry experts note that ethanol-blended fuel has different chemical properties compared to conventional petrol. Ethanol tends to absorb moisture more easily, carries lower energy content, and can slowly affect rubber and plastic parts in vehicles that were not originally engineered for higher ethanol blends. As a result, concerns have emerged over corrosion, weakening of seals and gaskets, fuel-line deterioration, injector damage, and added long-term stress on engines. Owners of older two-wheelers, small cars, and budget commuter vehicles remain particularly apprehensive, fearing that repair and replacement costs could place a heavy financial strain on them.

Industry estimates indicate that close to 80% of vehicles sold in the last 15 years were designed to run on E5 or E10 fuel blends. With the wider rollout of E20 petrol, many owners of older vehicles are increasingly concerned about higher maintenance expenses, shorter engine durability, and declining fuel economy.