PIN codes

PIN code stand for Postal Index Number code. It was introduced on independence day in 1972. It is six digits long. The first digit represents a zone and it is typically one or more states. There is one functional zone for army and military purpose. The first three digits together represent a geographical region or sorting facility at a main post office. Fourth digit represents the delivery route and zero digit means it is in main area of the post office. Fifth and sixth digits represent the delivery post office.

PIN codes start from North most states around Delhi and head south along the west coast in increasing order and then they head north along the east coast after reaching the south and head west and end in central India.

• 1 - Delhi, Haryana, Punjab, Himachal Pradesh, Jammu and Kashmir, Chandigarh
• 2 - Uttar Pradesh, Uttarakhand
• 3 - Rajasthan, Gujarat, Daman and Diu, Dadra and Nagar Haveli
• 4 - Goa, Maharashtra, Madhya Pradesh, Chhattisgar
• 5 - Andhra Pradesh, Karnataka, Telangana
• 6 - Tamil Nadu, Kerala, Puducherry, Lakshadweep
• 7 - Odisha, West Bengal, Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura,Meghalaya, Andaman and Nicobar Islands, Assam, Sikkim
• 8 - Bihar, Jharkhand
• 9 - Army Post office (APO) and Field Post office (FPO)

References
wikipedia PIN codes