Owners of petrol vehicles manufactured before 2023 are reporting worsening fuel efficiency and rising maintenance issues after the nationwide rollout of E20 petrol, with the proportion of respondents reporting mileage losses of more than 10% and increased wear and tear rising sharply over the past month, reveals a survey conducted by LocalCircles.According to the survey, 66% of owners of pre-2023 petrol vehicles said their vehicles’ fuel efficiency had fallen by more than 10% since early 2025, compared with 45% in a similar survey conducted in May 2026. The share of respondents reporting unusual wear and tear or increased repair requirements also rose to 55% from 29% during the same period.The findings come just over a year after India completed the nationwide rollout of E20 petrol in April 2025, achieving the target of 20% ethanol blending six years ahead of its original 2030 deadline. The survey also coincides with the Centre’s continued push towards higher ethanol blends and recent notification of fuel standards covering E22 to E30 petrol.Survey findingsThe LocalCircles survey received over 44,000 responses from owners of petrol vehicles purchased in 2022 or earlier across 305 districts.Among the 22,100 respondents who answered questions on mileage, 23% reported a decline of more than 20%, another 23% reported a decline of 15%-20%, and 20% reported a decline of 10%-15%. Overall, 66% said their mileage had declined by more than 10%, compared with 45% in May.Regarding vehicle condition, 22,668 respondents answered questions about wear and tear. Of these, 24% reported a major increase in repairs, 21% a moderate increase and 10% a slight increase. Overall, 55% reported increased wear and tear or repair requirements since early 2025, almost double the 29% recorded in the previous month’s survey.Survey cites possible reasonsThe report attributes the reported decline in mileage primarily to ethanol’s lower energy density compared with petrol. It argues that many older vehicles were designed for E5 or E10 fuel and lack the engine management systems required to optimise combustion with E20 fuel, potentially resulting in higher fuel consumption.On wear and tear, the report states that ethanol can absorb moisture and may affect metal and rubber components in fuel systems not originally designed for higher ethanol blends. According to the survey, this could contribute to corrosion, degradation of seals and hoses, and increased maintenance requirements over time in older vehicles.Government continues to defend the ethanol programmeThe survey comes amid an ongoing debate over the impact of ethanol-blended petrol on older vehicles.The Union Ministry of Petroleum and Natural Gas (MoPNG) recently rejected claims circulating on social media that E20 petrol causes engine failures or attracts insects, describing such content as misleading and unsupported by evidence. The ministry has maintained that no widespread engine failures attributable to ethanol-blended petrol have been reported.Gap between official position and consumer experienceLocalCircles said its findings are based on the reported experiences of vehicle-owners and should not be confused with misleading videos circulating on social media. The organisation said the survey focused specifically on measurable parameters such as mileage and maintenance rather than unverified online claims.The report noted that while the government has mandated that E20 petrol meet a minimum research octane number (RON) of 95 from April 2026 and automobile manufacturers are preparing retrofit kits for older vehicles, consumer concerns continue to persist.Calls for policy reviewBased on the survey findings, LocalCircles has urged policy-makers to consider allowing owners of pre-2023 petrol vehicles the option of purchasing lower ethanol blends such as E5 or E10 while the long-term effects of E20 continue to be assessed.The organisation also called for regular, transparent and independently auditable testing of ethanol content at fuel stations to ensure that petrol sold as E20 does not exceed the mandated 20% ethanol blend.The survey covered respondents from 305 districts across India, with 43% from tier-1 districts, 29% from tier-2 districts and 28% from tier-3, tier-4 and tier-5 districts. According to LocalCircles, all participants were registered users on its platform.This article was first published by Moneylife India.