Legacy cars pay the price. India’s push for E20 fuel — petrol with 20% ethanol — is meant to cut oil imports and emissions. But for 240 million legacy vehicles on road, the transition is bumpy.
The government notified in Feb 2026 that from April 1, 2026, all petrol must be E20. Vehicles made before April 2023 were designed for E5/E10. Consumer surveys show 66% of pre-2023 owners report mileage drop and higher component wear. SIAM warns organic chlorides in ethanol can damage fuel injectors within 200 km.
The technical problem is real. Ethanol absorbs water, causing phase separation in fuel tanks. It corrodes steel and rubber parts not built for it. At retail pumps, underground tanks in monsoon areas further contaminate fuel. The Ministry of Petroleum says contamination reports are “localized anomalies”, but mechanics across Delhi, UP and Maharashtra report similar complaints.
There is also a scientific split. The Engine Research Institute says mileage drop is minor and linked to driving habits. Independent experts and consumer forums disagree, citing real-world data.
The policy gap is choice. With E0/E10 being phased out, consumers have no option. Experts suggest dual-dispensing pumps, clear labeling, and certified retrofit kits for older vehicles. Brazil faced similar issues and resolved them with better standards and consumer information.
India cannot sacrifice 77% of its vehicle fleet for climate goals without support. E20 is unnecessary, however, it also needs a consumer-centric rollout, not a mandate without alternatives.