Nearly 50% pre-2022 petrol cars see lower mileage on E20 fuel: Survey

A nationwide survey shows 1 in 2 owners of petrol vehicles bought in 2022 or earlier report lower mileage after E20 petrol rollout, while 29 per cent also report unusual wear and tear

Nearly half of petrol vehicle owners who bought their vehicles in 2022 or earlier say their fuel efficiency has dropped in the last nine months, according to a new LocalCircles survey. 

The findings come as the government has mandated the supply of ethanol-blended petrol (E20) across the country. From April 1, 2026, E20 petrol must also meet a minimum Research Octane Number (RON) of 95 to improve fuel stability and reduce engine knocking. 

The survey received over 50,000 responses from owners of petrol vehicles bought in 2022 or earlier. Among those who took part in the survey, 69 per cent were men and 31 per cent were women. Nearly 45 per cent of the respondents were from Tier-I cities, while 29 per cent came from Tier-II cities. The remaining 26 per cent were from Tier-III, -IV and -V districts.

1 in 2 report drop in mileage

The survey asked petrol vehicle owners (with vehicles purchased in 2022 or earlier) whether their vehicle’s fuel efficiency had reduced since early 2025, when E20 became the default petrol grade nationwide. 

The survey asked petrol vehicle owners, whose vehicles were purchased in 2022 or earlier, whether they had seen a drop in fuel efficiency since early 2025, when E20 became the default petrol grade across the country. 

A total of 24,710 respondents answered this question. Of them, 25 per cent said their vehicle’s mileage had dropped by more than 20 per cent. Another 7 per cent reported a decline of 15-20 per cent, while 13 per cent said the reduction was between 10 and 15 per cent. About 7 per cent noticed a marginal dip of 1-2 per cent. Meanwhile, 27 per cent said there was no impact on mileage, and 21 per cent did not give a clear response. 

In total, about 1 in 2 respondents said their vehicle’s fuel efficiency had reduced in the past nine months. 

Ethanol has lower energy density than petrol, which can lead to lower mileage. 

29% flag unusual wear and tear

Apart from mileage concerns, a significant section of respondents also reported increased wear and tear. 

The survey asked owners whether they had experienced unusual levels of wear and tear or repair needs related to the engine, fuel line, tank, carburettor or related components since early 2025. 

A total of 25,686 respondents answered this question. Among them, 29 per cent said they had definitely experienced unusual wear and tear in their vehicles. Around 60 per cent said they had not noticed anything unusual, while 12 per cent did not give a clear response. 

To sum up, nearly 3 in 10 petrol vehicle owners with pre-2022 models confirmed experiencing higher-than-usual wear and tear or repair needs in the last nine months. 

Ethanol can absorb moisture and may affect rubber and plastic components over time if vehicles are not designed for higher ethanol blends. Many vehicles manufactured before 2022 were originally calibrated for E5 or E10 fuel.

Policy shift and vehicle readiness

India mandated E20 petrol nationwide in 2025 as part of its efforts to reduce crude oil imports and lower emissions. Most vehicles manufactured from 2023 onward have been engineered or recalibrated to run on E20 fuel. 

Automakers have introduced ethanol-resistant materials and updated engine settings in newer models. However, a large number of petrol vehicles currently on Indian roads are older models that may not be fully E20-compatible.