As the Here Maps App, previously known as Nokia Maps, is currently not available on Nokia ovi store for downloads in Pakistan, I found an alternate way to install Mobile maps on Nokia Asha 501.
Here Maps is the new version of Nokia Maps and Here Maps are powered by Nokia.
The Google Maps official app is also not available for Nokia Asha 501, so while searching for Mobile maps app I found old version of Google Maps Java App with touch screen support.
I installed the app and found it amazing and cool. You can use it to "Search Map", "Get Directions", "Satellite View", "Map View" and "Show Traffic".