Means you have to pay in advance the fuel cost for 10yrs of a non-fuel efficient car to buy a fuel efficient car
........ e.g:
Lets say I drive my car 50000Km per year, so if I have Diahatsu mira then:
50000/30 = 1666.666 liter of patrol per year = 1666.66 x 85 = Rs. 141666 per year.
If I use any of the current 1300cc car of pakistan say Suzuki Swift, then:
50000/15 = 3333.33 liter of patrol per year = 3333.33 x 85 = Rs. 283333 per year.
Difference = 283333 - 141666 = Rs. 141666 per year
Why not buy a fuel inefficient car like Swift & spend the extra money that you save in 5-10 years & enjoy the pleasure of driving 1300cc car. 
Moreover, I am sure the claimed mileage i.e 30km/ltr is for long route, not for pakistani roads. & in long, swift or any 1300cc car will easily give you 18-20Km/ltr.....
What you people say????