Kamal Ghorui
The government is set to change the way car mileage is tested and reported in India. This is expected to end the gap between claimed and real-world fuel efficiency figures. The Ministry of Road Transport and Highways (MoRTH) has proposed new rules that will require carmakers to test fuel consumption with the air-conditioning system both switched on and switched off, offering buyers more realistic mileage data.As per a draft notification issued last week, all passenger vehicles falling under the M1 category, including internal combustion engine cars and electric vehicles manufactured or imported in India on or after October 1, 2026, will have to undergo fuel efficiency testing with the air-conditioning system in operation. The testing will be carried out in line with AIS-213, the standard that defines procedures for measuring vehicle emissions and fuel consumption when the AC is running.At present, official mileage figures for cars in India are calculated with the air-conditioning system switched off. This often results in higher claimed efficiency numbers that do not match everyday driving conditions, where most users drive with the AC on for a large part of the year. Under the new regulation, manufacturers will be required to disclose two sets of figures (mileage with AC and mileage without AC) in vehicle user manuals and on their official websites.
AIS-213 takes into account the additional load placed on the engine or powertrain by the air-conditioning system and measures how this affects fuel consumption and emissions. The new regulation will apply uniformly to all passenger cars, whether they run on petrol, diesel, electricity or other powertrains. For consumers, this change could bring much-needed clarity. Buyers often face a common problem today as the actual fuel economy in daily driving is far lower than the claimed mileage, mainly because AC usage is not considered in current testing norms. With traffic congestion, long commutes, rising temperatures and year-round AC usage becoming normal across Indian cities, real fuel bills are often higher than what buyers expect at the time of purchase. By showing mileage figures with and without AC, customers will be able to make better-informed decisions, estimate running costs more accurately, and avoid unpleasant surprises at the fuel pump.
