Is BDA approval necessary condition given all other approvals are in place for a flat purchase?

Q: I've recently purchased a flat in a project that is under construction. The project has all the approval including municipal corporation (BBMP), fire, Airport authority, BSNL, BWSSB (Water and sewage)etc. But whenever I ask the builder about approval from BDA (Bangalore Development Authority), I get elusive replies. I have 2 questions, 1) Given that builder has all other approvals, can i assume that BDA approval is there (project is build on a non-agriculture residential land) 2) If no, which government body should i approach and what is the procedure to get that verified. I also want to add that i've got home loan on this property from SBI.