Amid E20 row, Nitin Gadkari says car owners can’t accurately check mileage on their own

Mangalore Today News Network

New Delhi, Jul 14, 2026: Union Road Transport and Highways Minister Nitin Gadkari has sparked fresh debate over the use of E20 ethanol-blended petrol, saying that car owners cannot accurately determine their vehicle’s fuel efficiency on their own and should instead rely on tests conducted by authorised dealers.

Speaking in an interview with ABP News on Monday, Gadkari responded to a journalist who claimed that her E20-compatible 2023 model car’s fuel efficiency had dropped from around 11 kmpl to 7 kmpl after switching to the mandatory E20 fuel.

When asked about the decline, Gadkari questioned how the mileage had been calculated. The journalist said she had relied on the mileage reading displayed on the car’s dashboard.

Gadkari maintained that accurate fuel-efficiency testing requires manufacturer-authorised diagnostic equipment.

"You and I can’t check the mileage. A car’s mileage can only be checked using a company-authorised dealer’s machine," he said.

The remarks come days after the Ministry of Petroleum and Natural Gas acknowledged that E20 petrol may reduce fuel economy by 3–5 per cent in some vehicles while defending the government’s ethanol blending programme.

In a recently released question-and-answer document, the ministry said that although some vehicles may experience a slight drop in fuel efficiency, mileage is only one factor to consider. The government has maintained that the programme is aimed at reducing crude oil imports, increasing ethanol blending, and lowering emissions.

The nationwide rollout of mandatory E20 petrol came into effect on April 1. Since then, several motorists have reported lower mileage, while some automobile manufacturers have expressed concerns about the fuel’s performance, particularly in older vehicles.

Can car owners measure mileage?

Experts say motorists can obtain a reasonable estimate of fuel efficiency, though it may not be perfectly accurate.

Modern vehicles calculate fuel economy using data from the engine control unit (ECU), fuel injection, and distance travelled. Dashboard mileage readings are generally considered estimates and are often within 2–5 per cent of manually calculated figures.

Automotive experts regard the full-tank method as the most reliable way to estimate real-world fuel efficiency. This involves filling the fuel tank completely, resetting the trip meter, driving normally until the next refill, and dividing the distance travelled by the amount of fuel added.

What do dealer diagnostic tools do?

Manufacturer-authorised diagnostic tools provide detailed information from the vehicle’s ECU and can assess the functioning of components such as fuel injectors, oxygen sensors, and airflow sensors. They can also detect engine faults and verify ECU calibration that may affect fuel consumption.

However, these tools do not directly measure real-world mileage under all driving conditions. Fuel efficiency also depends on factors such as traffic, road conditions, air-conditioner usage, tyre pressure, driving style, and vehicle load.