The builder is DS Max. He has building plan approval. Also have DC conversion. But he told as it under panchayat, he cannot have OC and CC. He also mentioned that once the area comes under Bangalore urber i.e BBMP premises. We need to take care of A-khata conversion and bare the charges.
This should actually have BDA approval. If it does not, there could be the problem of regularization that might have to be faced at a later date.
Check for deviations in the building or layout. That must be the reason that the builder might not have gotten BDA approval. BDA approval is also required to ensure that the land comes under residential usage. If not, BDA could take over the property tomorrow if it has been earmarked for other purposes. Even panchayat constructions and layouts are asked to get BDA NOC to prevent this from happening.
Do the neighbours have layout approval from BDA? BDA generally provides layout approval and not building approval.