The introduction of the PIN code by the P&T Department in 1972 ( 15th August) was a great advancement for the transportation and delivery of the letters, telegrams etc.
The PIN code was arranged in such a way that the Postman / Sorter can immediately find out the state, the district/city and the area in the city/town.
But even after 40 years many people do not use it regularly. Noting the PIN code helps early transportation and delivery. Do not forget to put the PIN code in the address.