Birth Certificate question??

My dad was born in Sion, Mumbai, India, way back in 1953, Sion hospital, but they didn’t issue him or register him a birth certificate?? This was before that birth certificate law of 63 or something. He called the hospital for one some years ago and they said they can’t find it or trace it. He got a notarized slip saying it’s untraceable (which is wtf?) Apart from that he does has a valid passport// marriage certificate // baptism (Christian) certificate and lot of information to tie him to Mumbai and his parents as well all their birth certificate and such. My question is, can they make one again? If there is no trace // loss of certificate. I’m sure they has to be a way? I tried checking which website or portal I could use but it’s confusing.