On August 15, 1972 India Post had introduced 6 digit Postal Index Number (PIN), known as Pin Code. 6 digit Pin Code indicates post office location. India has 9 PIN regions, in which 8 are for geographical location and the last one is for Army Postal Services.
First digit of PIN indicates Region, first 2 digits indicates Circle or sub division, first 3 digits of PIN indicates District (Revenue / Shorting) and Last 3 digits of PIN indicates Post Office.
First digit of PIN
1 - Northern Region
2 - Northern Region
3 - Western Region
4 - Western Region
5 - Southern Region
6 - Southern Region
7 - Eastern Region
8 - Eastern Region
9 - Army Postal Service (APS)
First 2 digits of PIN
11 - Delhi Circle
12 & 13 - Haryana Circle
From 14 to 16 - Punjab Circle
17 - Himachal Pradesh Circle
18 & 19 - Jammu & Kashmir Circle
From 20 to 28 - Uttar Pradesh & Uttaranchal Circle
From 30 to 34 - Rajasthan Circle
From 36 to 39 - Gujarat Circle
From 40 to 44 - Maharashtra Circle
From 45 to 49 - Madhya Pradesh & Chattisgarh Circle