India has moved a step closer to putting vehicles that can run on nearly pure ethanol on its roads. The Ministry of Road Transport and Highways (MoRTH) has amended the Central Motor Vehicles Rules, 1989 to formally recognize E100 alongside E85 in the country’s emission certification framework.
Announced on 26th October, the amendment creates a clearer approval pathway for flex-fuel vehicles designed to use high-ethanol blends. Until now, the rules provided for certification of vehicles running on up to E85, which is petrol blended with as much as 85% ethanol. The revized provisions now extend that framework to E100, a fuel made predominantly of ethanol.
E85 vs E100: What’s the difference?
The “E” in E85 and E100 stands for ethanol, while the number indicates the proportion of ethanol in the fuel. E85 contains up to 85% ethanol mixed with petrol, while E100 is essentially near-pure ethanol.
Flex-fuel vehicles are built to run on different petrol-ethanol combinations from a single fuel tank. Their fuel systems use components and materials suited to higher ethanol content and the engine management system adjusts its operation depending on the blend being used. Depending on the manufacturer’s certification, such vehicles may be approved for fuels ranging up to E85 or E100.
The technology is already in use in markets such as Brazil and the United States, where ethanol plays a larger role in transport fuel supply.
New certification framework
The amendment updates the emission certification provisions under Rule 115 of the Central Motor Vehicles Rules. It expressly includes E100 alongside E85 in the relevant certification tables, giving automakers a defined route to homologate and eventually sell E100-capable flex-fuel vehicles in India.
Vehicles certified for these fuels will still have to meet the emission and safety requirements applicable to their category. The notification also revizes biodiesel-related provisions, including a shift from B10 to B100 references and makes technical corrections to emission-testing tables. The changes took effect from the date of publication in the Official Gazette.
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Can existing cars use E100?
No. The government has been clear that the amendment does not make ordinary petrol or E20-compatible vehicles eligible for E85 or E100.
High-ethanol fuels are meant only for vehicles specifically designed and certified as flex-fuel vehicles. A car’s ability to run on E10 or E20 petrol does not mean it can safely use E85, let alone E100.
MoRTH has also said existing vehicle owners are not required to switch fuels or modify their vehicles now or in the future. Motorists should check the fuel-compatibility sticker on their vehicle and follow the guidance in the owner’s manual before choosing a fuel at a petrol pump.
A step towards ethanol-led mobility
The move fits into India’s broader push to expand ethanol use and reduce reliance on imported crude oil. Greater use of domestically produced ethanol could support energy security, and depending on the feedstock and production process help lower emissions across the fuel’s lifecycle.
For carmakers, the amendment provides the regulatory certainty needed to move E100 flex-fuel prototypes closer to commercial launch. For consumers, however, the immediate message is simple: E85 and E100 are not universal fuels, and only vehicles explicitly certified for them should use them.
The real-world impact will now depend on how quickly manufacturers bring compatible vehicles to market, how widely high-ethanol fuel becomes available, and whether the supporting supply chain develops at scale.
