bro its really difficult to put 15" rim in city 2001, if you will try it you will find the tyres will touch the springs cap of shocks, its better if you will keep the orignal size of rim or if you really want to increase the rim size take it to 14".
The other way to increase the size of rim to 15" is the only option that you put alum spacers behind the rim will cost you suspension and unbalanced drive.
best of luck
Whatever in short changing rim size to 15" will