You can't, and it's impossible everywhere in the globe, not just India, unless your birth year is off. The birth certificate is a public document maintained by the authorities that records the details of your birth; it cannot be amended unless the information is incorrect. In that case, they will issue a new one. However, there is a way to avoid this long process- simply go to a hospital where you were born or lived for several years and have them write you a new birth certificate. This document will have the updated information on it and will not be affected by the law regarding age discrimination. For example, if you were born in January 1970 then you would need to provide proof of this fact before you could be granted a passport with a younger age on it. An official document from the government office in charge of issuing passports will say that you are a person of legal age even though it may be on an old photo. This would allow you to travel without any problems despite being older than what's written on your passport. People often think that by inserting a date of birth higher than what they actually were born on that it will make them appear younger. This is not true; dates are measured in whole numbers from 1 to 12, so adding or subtracting them from your actual birthday will not change anything.