India’s current E20 petrol combines a 20% ethanol blend with a minimum 95 Research Octane Number. For the driver, the practical message is simple: the fuel now reaches the pump with a stronger and more consistent anti-knock standard.
Octane and mileage are different
Octane describes how well petrol resists uncontrolled combustion under pressure. A higher number gives the engine greater knock resistance. Mileage, by contrast, depends on the car’s calibration, traffic, load, terrain, temperature, tyres and the driver’s inputs.
A 95 RON figure describes knock resistance. It does not promise that every engine will travel farther on every litre.
What the driver should do
Use a busy, well-maintained outlet, keep the car at its manufacturer tyre pressure and follow the fuel grade stated in the owner’s manual. If you want to understand mileage, compare at least three complete full-tank intervals under broadly similar conditions.
One congested journey or one partial fill can distort the result. A short mileage dip is a signal to inspect the complete driving context, not a reason to assume a fuel-quality problem.
What the terms mean
E20 and 95 RON answer two different questions: the ethanol share of the petrol and the finished fuel’s resistance to knock. Check your owner’s manual for the grade and blend approved for your car.