The Union Minister, however, argued that tests for engine durability on a dynamometer and on-road vehicle tests have not shown any failures due to E20. In a written reply to the Lok Sabha, Gadkari said E20 fuel provides better acceleration, improved ride quality and approximately 30 per cent lower carbon emissions compared to E10 fuel. "The fuel efficiency of vehicles may be reduced by 2 to 6 per cent depending on the vehicle category and vintage. The tests for engine durability on a dynamometer and vehicle tests on road have not shown any failures due to E20," the minister said. The rollout of E20 petrol (80 per cent petrol, 20 per cent ethanol) has drawn criticism from opposition parties and some consumer groups, who have raised concerns about its impact on older vehicles not specifically designed for 20 per cent ethanol blends.