Postal codes in Pakistan were introduced on 1 January 1988 to speed sortation and delivery.
[1] and These codes are for the delivery post office in whose jurisdiction the residential, office, industrial, rural, or PO Box address falls.
Moreover, Pakistan Post Office is one of the oldest government departments in the South Asia.
In 1962 it was separated from the Telegraph & Telephone and started working as an independent post office.
For larger cities (Karachi and Lahore), there are a number of GPOs; however, the main one is the only one which has just the city's name attached to it (Karachi GPO and Lahore GPO).