The Ministry of Road Transport and Highways (MoRTH) has officially gazetted amendments to the Central Motor Vehicles Rules (CMVR), 1989, finalising the emission and testing protocols required to bring 100% Ethanol (E100) and 100% Biodiesel (B100) vehicles to the Indian market. The October 23 notification transitions the industry’s flex-fuel ambitions from prototype showcases to production-ready homologation.
The E100 Mandate for OEMs
A critical update in Rule 115 alters previous emission tables, explicitly replacing (E85) fuel parameters with (E85) or (E100). To prevent market confusion, MoRTH has inserted an explanatory note mandating that E85 or E100 can only be used in vehicles specifically designed and certified by Original Equipment Manufacturers (OEMs) as Flex-Fuel Vehicles (FFVs). This provides the long-awaited legal framework for two-wheeler majors and passenger vehicle OEMs to commercialise the flex-fuel prototypes they have been testing extensively. The notification also standardises standard gasoline blends as [(E10)/(E20)], formalising the ongoing nationwide rollout of E20 fuel.
The development should be seen in the context of Indian government successfully hit its 20% ethanol blending (E20) target in 2025, five years ahead of the original 2030 deadline set under the National Policy on Biofuels. Since April 1, 2026, E20 has been the mandatory, standard petrol available across all regular fuel pumps nationwide, effectively phasing out pure petrol and E10 blends.
While this hard pivot has caused some friction for owners of non-compliant older models, automakers have been manufacturing E20-material compliant vehicles since April 2023. The regulatory formalisation of E10 and E20 blends as [(E10)/(E20)] firmly aligns the emission testing protocols with the current pump reality.
Furthermore, following the initial rollout of E85 fuel promotion at select IOCL retail outlets in mid-2026, passenger vehicle OEMs like Maruti Suzuki and Toyota, alongside major two-wheeler manufacturers, now have the definitive homologation pathway required to launch their flex-fuel prototypes.
LCV and SUV Segments Get a 500kg Breather
In a highly strategic move for product planners, the government has raised the Gross Vehicle Weight (GVW) testing threshold from 3,000 kg to 3,500 kg. It expands the window for vehicles weighing between 3,000 kg and 3,500 kg to use the standard chassis-dynamometer drive-cycle emission limits rather than being forced onto heavy-duty engine-dynamometer testing (typically reserved for >3,500 kg).
B100 Opens New Decarbonisation Route for CVs
While ethanol dominates the passenger vehicle narrative, the commercial vehicle and construction equipment sectors gain a clear regulatory pathway with the substitution of (B10) with (B100) in testing parameters. It is pertinent to note that while the regulatory protocol for pure B100 testing is established, commercial adoption in heavy transport faces acute feedstock availability bottlenecks and high production costs compared to conventional diesel.
Additionally, B100 homologation provides the regulatory roof, but OEM field deployment will predominantly focus on B20-compatible platforms before pure B100 fleets scale in dedicated pilot operations. Most global and Indian heavy diesel engines are validated for up to B20 blends without major fuel-system re-engineering. Running B100 requires dedicated fuel pre-heaters, specialised elastomers, and tight maintenance intervals due to fuel oxidation and gelling at lower temperatures.
Supply Chain Pivot
With the regulatory grey areas closed, the onus now shifts to the Tier-1 supply chain. Component manufacturers will need to rapidly scale localised production of ethanol-compliant fuel lines, specialised combustion sensors, and corrosion-resistant engine internals to support the upcoming wave of OEM flex-fuel launches.