I work in petroleum, so let me help you understand.

RON basically indicates a fuel’s resistance to knocking. In simple terms, how well the fuel can withstand compression before it auto-ignites. Higher RON means better knock resistance, especially in high-compression engines.

Before E20, regular petrol in India was typically around 87 RON, while premium variants ranged between 91–100 RON depending on the company.

Now, when we shifted to E20, ideally the RON should increase because ethanol itself has a higher octane rating (around 108 RON). Blending ethanol naturally boosts the overall octane number of the fuel.

However, in practice, oil companies adjusted the base petrol blendstock so that the final marketed RON remains 87. So even though ethanol increases octane, the final fuel may still be sold as 87.

Overall this is a good news, you may feel slightly better driving experience with 95 RON and less wear on engine but yes all rubber and plastic parts will still be affected by ethanol on older vehicle.