From the article:
The fuel efficiency numbers on the list will be based on the reviews that we have of the vehicles and will be tallied in terms of points for their respective fuel economy numbers. This means that if a vehicle gets 8 km/L in the city and 16 km/L on the highway then it gets a total of 24 points. In the event of a tie, the vehicle with the higher city fuel efficiency number will take the win. If there are two variants of the vehicle tested, then the model with the higher fuel efficiency figures will be considered. This will better represent what the vehicle is capable of in terms of giving you the best mileage for as little fuel as possible.