In a July session of the Rajya Sabha, Minister Nitin Gadkari explained that tests on BS‑III vehicles from 2005 to 2016 showed that some rubber parts and gaskets may need replacement when driven on E20. He said the change can be handled during routine servicing.
The tests, carried out by Indian Oil Corporation, the Indian Institute of Petroleum, SIAM and the Automotive Research Association of India, found no need to modify engines of cars or two‑wheelers for E20. BS‑VI vehicles also met emission norms while running on the fuel.
Gadkari added that legacy vehicles did not show any significant changes in performance or abnormal wear. There were no reports of problems in drivability, start‑up, metal or plastic compatibility.
The government’s detailed study was not released to the public, but the Ministry of Heavy Industries said the testing covered durability, drivability, cold start, corrosion resistance, material compatibility, fuel‑system reliability, emissions and fuel‑efficiency.
When asked about mileage, the minister said fuel efficiency depends on many factors such as driving habits, oil changes, filter cleanliness, tyre pressure, wheel alignment and air‑conditioning load. An inter‑ministerial committee under NITI Aayog in December 2020 had also examined vehicle compatibility and mileage.
The Heavy Industries Ministry was questioned in the Lok Sabha about the cost impact on owners of older vehicles. It admitted that no assessment of extra repair or maintenance costs had been done and that there is no plan to provide an advisory, compensation or transition support for owners of vehicles not originally compatible with E20.
In the Rajya Sabha on July 20, CPI(M) MP V. Sivadasan asked about complaints and whether E0 or E10 would remain available. The Petroleum Ministry said it had not received any widespread complaints about vehicle performance linked to E20, though media reports and social‑media posts were noted.
Field data shows that more than 20 crore two‑wheelers and over 3 crore petrol cars have run on E15 or higher blends for more than three and a half years, and E19‑E20 for over two and a half years, without evidence of widespread engine failure. A leading manufacturer serviced 2.84 crore vehicles in 2025‑26, including 1.5 crore not originally certified for E20, and reported no corrosion or abnormal wear.
Manufacturers continue to honour warranties for vehicles running on E20, indicating acceptance of the testing and validation process.
The government has ruled out restoring E0 or E10 alongside E20. Oil marketing companies are directed to supply motor spirit with up to 20% ethanol that meets BISO specifications. From 1 April 2026, ethanol‑blended motor spirit with a minimum RON 95 will also be notified.
Maintaining separate supply chains for E0, E10 and E20 across more than one lakh fuel outlets would raise logistics complexity and costs. The ethanol‑blending programme began with a pilot in 2001, followed by E5 in 2006. Average blending rose from 1.53% in 2013‑14 to 19.2% in 2024‑25, reaching the 20% target in December 2025. The transition is described as phased and based on consultations with manufacturers, testing agencies and oil marketers.