The central government has amended the Central Motor Vehicles Rules, 1989, to recognise E100 ethanol fuel alongside E85 for specially designed flex-fuel vehicles. However, regular petrol cars and vehicles certified only for E20 fuel cannot automatically use these higher ethanol blends.

The Ministry of Road Transport and Highways (MoRTH) notified the changes through Gazette notification G.S.R. 911(E), dated October 23, 2026. The amendments revise Rule 115, which governs vehicle emission standards.

E85 contains around 85% ethanol, while E100 refers to ethanol fuel. E20 contains 20% ethanol blended with petrol. Under the revised rules, E85 and E100 are intended for vehicles specifically designed by original equipment manufacturers (OEMs) as flex-fuel vehicles. Owners must follow their manufacturers’ fuel compatibility specifications.

The notification also replaces the B10 biodiesel reference with B100 in a specified entry under Rule 115(18). B10 contains 10% biodiesel, while B100 represents pure biodiesel. The change does not automatically make all existing diesel vehicles compatible with B100.

The government has also increased the gross vehicle weight threshold in the heading of a specified emission-related table from 3,000 kg to 3,500 kg. This change does not revise vehicle registration categories or driving licence requirements.

Other amendments replace the existing E10 and E reference with E10 and E20 in a relevant table. The notification also removes wording related to manufacturer specifications from a particular note on E10 petrol.

Additional technical changes clarify HCNG as hydrogen plus CNG, correct emission table headings and chemical notation, and revise a numerical entry from 60 to 600. The amendments also correct the unit from Mg/kWh to mg/kWh, change the E100 vehicle annexure reference from Annexure S to Annexure SA, and replace “Compression” with “Comparison” in a specified explanatory note.

The revised rules will take effect from their publication in the Official Gazette, except where otherwise specified. They follow draft amendments published on April 27, 2026. The ministry said it considered objections and suggestions received from stakeholders before finalising the changes.

For vehicle owners, the amendments do not mandate a switch to E85 or E100. They also do not announce a timeline for E100’s commercial availability or a nationwide shift to higher ethanol blends.