Shastri Bhavan

Regional Passport Office (RPO) was established in George Town in Chennai (formerly Madras) in the year 1955.  In the year 1966, it was shifted to the Govt. owned  premises of Shastri Bhavan, Bureau of Immigration, located at 26, Haddows Road, Nungambakkam, Chennai - 600 006, where a number of other Central Govt. Offices are also located. 

http://immigrationindia.nic.in
PIO
http://immigrationindia.nic.in/FAQ_PIO.htm

Visa extension
http://immigrationindia.nic.in/FAQ_Visa_Extensions.htm