New Delhi: With E20 petrol (20% ethanol and 80% petrol) now the standard fuel across India, many motorists have reported reduced mileage and raised concerns about the impact on older vehicles. As the government also considers moving towards E25 petrol, experts, automakers and consumers are debating the benefits and challenges of higher ethanol blending.
The primary concern is fuel efficiency. Ethanol contains less energy per litre than petrol, meaning vehicles generally travel a shorter distance on the same amount of fuel. Industry estimates suggest E20 can reduce mileage by around 2–4%, while some owners of older vehicles have reported even larger drops depending on engine design and driving conditions.
Owners of vehicles manufactured before widespread E20 compatibility have also expressed concerns about engine components. Higher ethanol content can absorb more moisture, increasing the possibility of corrosion in fuel-system parts, rubber seals and metal components over long periods, particularly in engines not originally designed for higher ethanol blends. Some users have also reported harder cold starts during winter because ethanol has different combustion characteristics than conventional petrol.
However, the Central Government, the Automotive Research Association of India (ARAI) and major automobile manufacturers maintain that extensive testing has found no evidence of significant engine damage from E20 fuel when used as intended. Carmakers including Maruti Suzuki, Hero MotoCorp and Toyota have said service data from millions of vehicles does not indicate widespread ethanol-related failures, although they acknowledge a modest reduction in fuel economy.
The government is promoting ethanol blending as part of its strategy to reduce crude oil imports, improve energy security, lower greenhouse gas emissions and provide a larger market for farmers producing crops such as sugarcane and maize. India achieved its 20% ethanol blending target ahead of schedule and is now studying a gradual transition to higher blends such as E25, followed by E85 and E100 for flex-fuel vehicles.
Unlike countries such as Brazil, Indian motorists currently have limited choice at fuel stations, with E20 becoming the default petrol in many areas. Brazil’s long-running ethanol programme pairs higher blends with flex-fuel vehicles and gives consumers multiple fuel options, a model that many experts believe India could adapt before expanding beyond E20.
While the government says any move to E25 will follow further testing and consultation, automakers have called for additional validation of vehicle compatibility, fuel infrastructure and nationwide supply before introducing higher ethanol blends. The debate highlights the challenge of balancing environmental goals with consumer costs, vehicle performance and long-term engine durability.
