Is it safe to buy DTCP approved plots?

I have come across a land in Chennai which is being claimed as having DTP approval. While am not given the full form of DTP, I am being told that it is different from DTCP and is an older approval which is still valid today. This land is outside the Chennai city limits and is closer to the beach. My guess is that it could be a local body approval at that time ( several years go )..Pls guide me if it is okay to go ahead with this land.