56% owners of older vehicles faced mileage, fuel efficiency issues after E20 switch: Survey

More than half of respondents with older vehicles reported reduced mileage or fuel efficiency due to the usage of ethanol-blended E20 petrol. The survey, conducted by LocalCircles, suggested that a significant share of older petrol vehicles may be experiencing a combination of efficiency, performance and maintenance-related challenges.

The survey, which received over 22,000 responses from owners of pre-2023 petrol vehicles across 302 districts, asked respondents about major issues experienced since early 2025. 

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Here’s what the survey found from 22,574 respondents:

• 56% reported reduced mileage or fuel efficiency
• 43% cited engine performance issues such as power loss, knocking or rough idling
• 34% reported increased repair and maintenance costs
• 20% experienced fuel system issues
• 19% reported increased engine heating
• 19% said they had experienced multiple issues

Only 26% said they had not faced any issues, and 16% said they had started facing problems. Since respondents could select more than one option, the total exceeds 100%. 

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The survey follows an earlier LocalCircles study released on June 5, 2026, which focused on reduced vehicle mileage after the switch to E20 petrol and its financial impact. That survey, which covered over 42,000 owners of pre-2023 petrol vehicles, found that 52% had incurred ₹5,000–25,000 or more in additional expenditure since early 2025 due to reduced mileage and/or increased repairs. 

It also found that 55% wanted the option to switch back to E0 or E10 petrol, either immediately or if priced similarly to E20, while only 12% preferred to continue using E20.

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