Birth certificate

Hello I am from Kerala but was born in chennai in 1996. I have a birth certificate with me in which name is not written (It seems that you could get a birth certificate without name then) . Now i want to have the birth certificate with name. I tried to retrieve from corporation website but couldn't get it 1) What all docuements should i carry for this ? 2) How many days should i be in chennai as i have to plan my bookings accordingly Please help! TIA