ExplainedFuel
E20 petrol explained: what the 20% ethanol blend means and why Karnataka's test result is disputed
Karnataka says petrol at some pumps carried up to 31.2% ethanol, and the three state-run oil companies say their petrol stays within 19% to 21%. What E20 is, how it is checked, and what drivers should know.
The short answer
E20 is petrol blended with about 20% ethanol, a fuel made from sugarcane, grain and other farm produce. India reached that blend in 2025-26 and sells it under the BIS standard IS 17021. On November 6, 2026 Karnataka said 63 samples from seven districts ran from 13.5% to 31.2% ethanol, while Indian Oil, HPCL and BPCL say 893 samples from 27 states and Union Territories tested between 19% and 21%. Both sides have asked for the other's records, and no joint test has been announced.
What is E20 petrol?
It is ordinary petrol with about 20% ethanol mixed in. Ethanol is an alcohol made by fermenting sugarcane juice, molasses, damaged grain or maize. Refiners mix it with petrol before it is sent to pumps, so a driver filling up at an Indian Oil, HPCL or BPCL outlet gets E20 unless a pump sells a different grade.
The letter E and the number show the share of ethanol. E10 is 10% ethanol, E20 is 20%. The Bureau of Indian Standards covers the fuel under IS 17021, which the oil companies cite as the specification their petrol follows.
How did India get to 20%?
Through a government blending programme that began from a base of under 1.5%. According to the Press Information Bureau’s fact sheet of July 5, 2026, the blend rose from under 1.5% in 2013-14 to 20% in 2025-26, five years ahead of the original 2030 target. Ethanol procurement grew from about 38 crore litres to a projected figure of over 1,200 crore litres, and ethanol production capacity from 421 crore litres in 2014 to about 2,000 crore litres in 2026.
Why does the government want it?
To import less crude oil and pay farmers more. India imports about 88.5% of its crude oil. The fact sheet says blending has saved over ₹1.90 lakh crore in foreign exchange since 2014-15, substituted more than 310 lakh tonnes of crude, and put over ₹1.60 lakh crore into farmers’ hands. It also credits the programme with cutting about 930 lakh tonnes of carbon dioxide.
The sheet adds a caveat: ethanol was cheaper than petrol in 2020-21, but the price paid for it has since risen above the cost of refined petrol.
E20 in numbers (as of July 2026)
- under 1.5% to 20%blend, 2013-14 to 2025-26
- 421 to 2,000ethanol production capacity in crore litres, 2014 to 2026
- ₹1.90 lakh croreforeign exchange saved since 2014-15
- 88.5%share of crude oil India imports
Does E20 reduce mileage?
Slightly, according to the government and carmakers. Ethanol carries less energy per litre than petrol. The fact sheet says Maruti Suzuki estimates that a car rated at 20 km a litre loses about 0.6 km a litre on E20. It also says the fuel’s higher octane rating lets engines run smoothly, and that insurers and manufacturers say E20 does not affect warranty or insurance for compliant vehicles.
Many drivers of older cars disagree. Karnataka’s food and civil supplies minister, Rizwan Arshad, said the state began testing after motorists complained of poorer mileage and frequent repairs.
What did Karnataka find?
Readings between 13.5% and 31.2%. On November 6 the state said it had drawn 63 petrol samples in Bengaluru, Bengaluru Rural, Kolar, Chikkaballapura, Ramanagara, Tumakuru and Mangaluru and tested them at the Shriram Research Institute in Bengaluru. The highest, 31.2%, was an Indian Oil sample, and an HPCL sample read 30.5%. The minister said nearly four in five samples were above 20%.
Karnataka has asked the Centre to act against suppliers of petrol above 20%, to label the blend at each pump and to compensate affected vehicle owners.
What do the oil companies say?
That the state’s samples were collected and tested without them. Indian Oil, HPCL and BPCL say no representative took part, the laboratory is not one named in the fuel control order, and the test certificates do not state the method. They also say the densities the state reported do not fit ethanol levels so high.
The companies point to their own monitoring: all 893 samples from 27 states and Union Territories fell between 19% and 21%, including 56 from Karnataka averaging 19.30%. They have asked the state for complete sampling records and joint testing at an authorised laboratory. Opposition leader Rahul Gandhi has taken up Karnataka’s claim and asked the Prime Minister how much ethanol is in petrol.
What happens next?
The question is a method question, and a joint test would settle it. The two sets of numbers cannot both describe the same fuel at the same pumps. Which one is right depends on how the samples were drawn, stored and measured. Until both sides share records, as of November 2026, the 31.2% figure is a state finding that the supplying companies contest, and the 19% to 21% range is the companies’ own report.
The documents
- E20 fact sheet, July 5, 2026Press Information Bureau, July 5, 2026