NEW DELHI: For the second time in the past 11 months, country’s automobile majors have come to back govt’s mandatory 20% blending of ethanol in petrol (E20) — amid some genuine concerns and some misinformation surrounding the adverse impact of E20 on vehicles that were manufactured before April 2023. TOI looks at why the controversy is on.
Mileage/Consumers complaints
For most vehicle owners, mileage still remains the key factor while buying a vehicle. There have been numerous complaints that the mileage of vehicles has dropped since the full roll out of E20 — an issue not just flagged on social media, rather a common talking point in workplaces, and at social gatherings. Govt and automobile companies have maintained that there is 3-4% reduction in mileage due to E20 fuel in vehicles that are non-compliant. They refer to findings of a study conducted by Automotive Research Association of India (ARAI), Indian Oil Corporation and SIAM in 2021. It said fuel consumption of vehicles with E20 increases 2-6% compared to E10, and the percentage varies from vehicle to vehicle.However, vehicle owners don’t buy this, as the real mileage loss is more. They need to buy more E20 and that too without any reduction in price to compensate for mileage loss. Automobile companies and govt have maintained that mileage depends on factors, including tyre pressure, driving pattern, gear selection, and vehicle maintenance.
Impact on vehicle engine and materials
Govt and vehicle manufacturers have referred to ARAI report of 2021 to refute claims of impact of E20 fuel on vehicles. The report said there was “no significant discoloration or pitting or any other type of corrosion” in any metallic components tested. The full report, which TOI has seen, concluded that “fuel system material coupons made of a certain elastomer (rubber) like NBR-PVC blend performed inferior with E20 compared to E10”. It added that as per SIAM, “rubber parts for fuel system components used in vehicles, such as hoses, gaskets/ seals and O-rings are showing deterioration and may need replacement for using E20”.
India’s E20 programme
India achieved 20% ethanol blending in April 2025, ahead of the earlier target of 2030, meaning normal petrol at every pump has 20% ethanol. People involved in govt’s ethanol blending programme say had the target not been pushed, almost all E0 (100% petrol) vehicles manufactured prior to 2012 and a large share of E10 (10% ethanol) compliant vehicles manufactured from 2013 onwards would have completed 15 years.However, the significance and benefit of E20 caught attention after the US-Israel attack on Iran disrupted global fuel supply and pushed crude prices. Govt has said ethanol blending programme has reduced oil imports by 4.5 lakh barrels per year and saved foreign exchange.
Why controversy at peak now
While some parts of the country started getting E20 early, availability across the nation was achieved only in April 2025. So, the number of complaints about drop in mileage and other negative impacts have increased. The impacts are more in case of vehicles manufactured before 2012.Bureau of Indian Standards (BIS) notifying fuel standards for E22, E25, E27 and E30 has further raised the speculation of govt increasing mandatory blending. Officials are tight-lipped about where and when this decision was taken. However, govt has maintained any further increase in ethanol blending will be done after proper research and due consultation with stakeholders. Higher blending would even impact E20 vehicles.
Can govt give option of 100% petrol & E20 at pumps for consumers to opt
After going for mandatory 20% ethanol blending there is hardly any possibility of going back. However, experts say govt should go for higher blends of ethanol as an optional fuel at stations so that vehicles that are compatible can go for them, something similar to the practice in Brazil.
