How Much Ethanol is Too Much Ethanol?

Amid rising concerns over performance, efficiency, and long-term readiness, here's what India's rapid shift to ethanol-blended fuels E5, E10, and E20, means for everyday motorists

- By Kanaad Chatterjee

With India achieving its 20 per cent ethanol-blended petrol target in March 2025—five years ahead of the 2030 deadline—after crossing 10 per cent blending in June 2022, multiple reports have highlighted its impact on engines and mileage. While the government highlights energy security and farmer benefits, motorists remain divided over whether the gains outweigh the trade-offs.

Amidst all the commotion, three alphanumeric codes have been at the centre of the confusion. E20, E10 and E5 are nothing but labels for petrol blended with ethanol by volume—20 per cent, 10 per cent, and 5 per cent respectively. In fact, India has used E5 and E10 for years. In 2025 the country accelerated a nationwide rollout of E20 and at many pumps it is now the only petrol on sale. The shift is meant to cut oil imports, lower emissions, and channel more money to farmers who supply ethanol.

Pros (Why Blend At All?)

Ethanol is a renewable fuel (made mostly from sugarcane and grains in India). Blending reduces crude-oil use and foreign-exchange outgo while supporting rural incomes. Technical work led by the government and testing agencies showed regulated emissions can be lower with E10 and E20 than with neat petrol, and India set a roadmap nudging automakers to make vehicles “material-compatible” and, from newer model years, “E20-tuned.”

Cons (The Trade-Offs You'll Feel)