50% older petrol vehicle owners report mileage drop after E20, finds survey

A recent LocalCircles study found that 29 per cent of petrol vehicle owners also faced unusual engine wear and tear as India pushes ahead with higher ethanol fuel blends beyond E20

Nearly half of petrol vehicle owners of four- or two-wheelers purchased in 2022 or earlier have reported a decline in fuel efficiency since the nationwide rollout of E20 petrol, according to a survey released by LocalCircles on Monday. The survey said that nearly three in 10 vehicle owners have experienced unusual engine wear and tear.

 

In February, the Centre notified that oil companies would be required to sell petrol blended with up to 20 per cent ethanol and with a minimum Research Octane Number (RON) of 95 across all states and Union Territories. The rule came into effect from April 1 as part of the government’s broader strategy to reduce crude oil imports and support domestic ethanol production.

   

However, concerns among owners of older petrol vehicles around reduced mileage, harder cold starts, and unusual engine wear and tear have only intensified. The LocalCircles survey stated that since the rule came into force, many consumers, especially those whose vehicles were originally engineered for E5 or E10 fuel, said their on-road experience does not match the official Automotive Research Association of India (ARAI) estimate of a 1-6 per cent dip in fuel efficiency.

 

The report said ethanol-rich fuel behaves differently from conventional petrol as it absorbs moisture more readily, has lower energy density, and can gradually degrade rubber and plastic components in vehicles not designed for higher ethanol blends. This, it said, raises concerns around corrosion, deterioration of seals and gaskets, fuel-line damage, injector wear, and long-term engine stress in older vehicles.

 

It also flagged growing concerns over the declining availability of lower-ethanol fuel options. Since E20 has effectively become the standard petrol grade across most regions, owners of older vehicles have limited alternatives, while premium low-ethanol petrol remains substantially more expensive for ordinary consumers, the survey noted.

What did the LocalCircles survey find about E20 petrol mileage?

The survey, which received over 50,000 responses from owners of petrol vehicles across 301 districts, found that one in two owners of vehicles purchased in 2022 or earlier reported a fall in mileage in the last nine months. Around 25 per cent of respondents said fuel efficiency had dropped by over 20 per cent, while another 20 per cent reported a decline between 10 and 20 per cent.

 

Furthermore, around 29 per cent of respondents said they had experienced unusual wear and tear or repair requirements related to the engine, fuel line, tank or carburettor since early 2025. Common complaints included engines heating faster, rough idling, increased vibration, harder cold starts and lower pickup.

Why are older petrol vehicles facing E20 compatibility concerns?

The report, citing industry estimates, said that nearly 80 per cent of vehicles sold over the past 15 years were originally engineered for E5 or E10 petrol, raising concerns about compatibility with higher ethanol blends. The survey comes at a time when the government is preparing for higher ethanol blends such as E22, E25 and E30.

 

Earlier this month, the Bureau of Indian Standards notified specifications for higher ethanol-petrol blends as India accelerates its ethanol blending programme beyond E20.