We note you have a 2021 Honda City so you really don’t need to worry about using E20 petrol. Honda has officially stated on its website that "All Honda cars manufactured in India since 1 Jan 2009 have been E20 Material Compatible and customers can use the E20 fuel in their existing Honda cars without the need of changing any part in the car”
From our lab tests, Shell petrol currently has a slightly lower ethanol percentage but it too will eventually move to a full 20 percent blend as supply stabilises. E20 has less energy than pure petrol, so you can expect some drop in fuel efficiency, but there is no evidence that it will cause significant damage to a 2021 City’s fuel system or engine, and the issue has been unnecessarily overblown on social media. The best advice is to tank up at a reputable outlet and continue using your car as normal. Don’t worry about any E20 damage.