NEW DELHI: Indian cars are likely to deliver some extra miles on every litre of fuel as the government has notified fuel efficiency guidelines that auto makers must follow from April 2017.Cars and utility vehicles are expected to deliver at least 18.2 km to a litre of fuel, a 15% increase over the existing average mileage. To meet this requirement, a manufacturer must ensure that average fuel efficiency of all the models manufactured by it is at least 18.2 km per litre.That means, an auto maker can still sell cars that deliver less than 18.2 km. But it needs to make sure that it also sells vehicles that offer higher mileage so that the average of all models meets the rule.From April 2022, the average will be lifted to 22 kmpl. Separate standards are likely to be announced for trucks and buses. "It will change the performance of locally manufactured cars. While some cars could be phased out, there would be a giant leap in technology that would come at no extra cost, but would allow improved engines and efficient cars on roads," said a senior government official working on the guidelines.The standards are expected to take India into the league of a few advanced nations, like the US, Japan, Germany and China which strictly enforce such rules and carry harsh penalties for violation. The finer details for the implementation and procedures for penalties would be decided by the Ministry of Road Transport and Highways Standards have been framed by the Bureau of Energy Efficiency . An agency executive said benefits in terms of fuel saving from this could be more than Rs 90,000 crore a year for India. Even as cars will get heavier – as they will have to strengthen body structure and bring in more features as the government has notified crash test standards, to be followed from October 2017 – the new policy intervention would lead to improved mileage in vehicles and bring direct benefits to consumers. Average weight of vehicles has been kept at 1,145 kg to determine fuel efficiency.