It was during 1972 that the Indian Postal Department introduced the concept of PIN (Postal Index Number) codes. These are 6 digit codes that are assigned to specific geographical areas in a state. The first two digits represent the state and the last four digits represent the district, sub-district and sorting code. The PIN code of Arunachal Pradesh starts with “79”. Currently, there are close to 280 Postal Index Number codes in the state. Out of these, some of the cities with a large number of codes are Lohit (33), Papumpare (32), Tirap (30), East Siang (29) and West Siang (27).