Petrol blended with 20 per cent ethanol (E20) may reduce vehicle fuel efficiency by 2 to 6 per cent depending on the type and age of the vehicle, but extensive testing has found no evidence of engine failures caused by the fuel, Union Road Transport and Highways Minister Nitin Gadkari informed Parliament.
In separate written replies to the Lok Sabha and Rajya Sabha on Thursday and Wednesday, Gadkari said studies conducted by government agencies and automobile manufacturers concluded that E20 fuel is safe for vehicles. However, he noted that some BS-III vehicles manufactured before 2016 may require replacement of certain rubber components and gaskets during routine maintenance.
Replying to a question in the Lok Sabha, Gadkari said a joint study on the impact of E20 fuel on BS-III, BS-IV and BS-VI E10 petrol two-wheelers and four-wheelers was carried out by the Automotive Research Association of India (ARAI), the Society of Indian Automobile Manufacturers (SIAM) and Indian Oil Corporation Ltd (IOCL).
He said the study included standard certification tests as well as customised testing protocols developed in consultation with Original Equipment Manufacturers (OEMs).
"The fuel efficiency of vehicles may be reduced by 2 to 6 per cent depending on the vehicle category and vintage. The tests for engine durability on a dynamometer and vehicle tests on road have not shown any failures due to E20," Gadkari said.
The minister added that E20 fuel offers better acceleration, improved ride quality and nearly 30 per cent lower carbon emissions compared with E10 fuel.
Addressing concerns about older vehicles, Gadkari told the Rajya Sabha that the studies found no need for engine modifications in cars or two-wheelers. According to him, even older vehicles did not show significant changes in performance or abnormal wear and tear when operated on E20 fuel.
He said the research found no issues relating to drivability, startability, metal compatibility or plastic compatibility.
However, Gadkari noted that tests conducted on BS-III vehicles introduced from April 1, 2005, and manufactured before 2016 indicated that some rubber parts and gaskets may need replacement when using E20 fuel.
"Only in case of testing done on BS-III vehicles introduced from 1st April, 2005, and manufactured prior to 2016, some rubber parts and gaskets may require replacement, which can be easily managed during routine servicing regime of the vehicle," he said.
The rollout of E20 petrol, which consists of 80 per cent petrol and 20 per cent ethanol, has faced criticism from Opposition parties and some consumer groups. Critics have questioned whether all vehicles are fully compatible with the fuel, raised concerns about reduced fuel economy and increased maintenance costs, and sought clarity on liability in the event of engine or fuel system problems.
The government has maintained that the transition has been implemented through a phased and scientifically validated process. Automobile manufacturers have also said they continue to honour warranty claims for vehicles using E20 fuel. Opposition parties have repeatedly called for greater transparency regarding vehicle compatibility and consumer protection.
Gadkari said the Ethanol Blended Petrol (EBP) Programme has been implemented through a phased, calibrated, scientifically validated and consultative approach involving NITI Aayog, automobile manufacturers, oil marketing companies (OMCs), ARAI, SIAM, the Indian Institute of Petroleum (IIP) and other technical institutions.
He also informed the Rajya Sabha that an Inter-Ministerial Committee (IMC), constituted under NITI Aayog on December 26, 2020, had comprehensively examined issues related to vehicle compatibility and fuel efficiency. The committee's assessment drew on research conducted by IOCL, ARAI and SIAM.
According to Gadkari, the committee's Roadmap for Ethanol Blending in India 2020–25, released in June 2021, was prepared after extensive consultations with automobile manufacturers, oil companies and agricultural experts. The report assessed material compatibility, engine calibration, fuel systems, drivability, durability, emissions, fuel efficiency and other vehicle performance parameters before the introduction of E20 fuel.
The minister said the EBP Programme began with a pilot project in 2001, followed by the introduction of E5 fuel in 2006. Although ethanol blending remained around 1.53 per cent until 2013-14, the government gradually increased the blending level after establishing the necessary production capacity, infrastructure and regulatory framework.
He added that E15+ blended petrol has been in widespread use for more than three and a half years, while E19-E20 fuel has been in use for over two and a half years.
Before rolling out E20 fuel in April 2026, the government conducted extensive laboratory studies, durability tests and field validation covering engine durability, material compatibility, fuel systems, corrosion resistance, drivability, emissions, fuel economy and overall vehicle performance, Gadkari said.
Highlighting the scale of adoption, the minister said more than 20 crore two-wheelers and over 3 crore petrol cars have operated on ethanol-blended fuels without any verified evidence of widespread engine failure or vehicle breakdown attributable to ethanol blending.
"Manufacturer service data confirm that there is no abnormal corrosion, wear or reduction in vehicle life due to E20 fuel," he said, adding that manufacturers continue to honour warranty obligations for vehicles using E20 fuel, reinforcing confidence in its safety and reliability.
BS, or Bharat Stage, refers to India's emission standards that prescribe permissible limits for pollutants such as carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons (HC) and particulate matter (PM).
