After alot of research i have found out that no vitz after 2005 gives more than 10km\l in city, it gives great economy on highway upto 18km\l easily, those people who do not own toyota vitz shouldn't claim anything and as for those people who do, if they are getting more than 10km\l then firstly they are really lucky, secondly their driving style matches that of highway i.e if your driving in islamabad or lahore, its not typical city traffic, its just like driving on highway. But for people in smaller cities like abbottabad or any other city in Pakistan with conjusted roads it is guaranteed you wont get average above 10km\l even if you drive calmly without rapid acceleration.
So for all my brothers on pakwheels, if you want to buy vitz, it is no doubt a wonderful car but it is not fuel efficient.