Resale Flat without OC but other documents available

I live in Vashi, Navi Mumbai Maharashtra.I am trying to purchase a property which has all documents except OC.The property is 10 years old and the seller has purchased it from the builder.On Enquiry,the OC application has been filed and I have been shown documents dated 2014.I was informed that due to CRZ regulations the OC has been delayed. Canara bank has taken cognisance of the fact and is willing to give the loan.There are other buildings near the to be purchased flats which do not have CC and OC.The flat to be purchased was built under the 12.5%scheme and has CIDCO approval.Only OC is not there. Is it right to go with the purchase. What are the CRZ regulations as of now.Also guide me whether a sale deed needs to be registered before sanctioning of Loan.Canara Bank is asking me to go ahead with the agreement.But my issue is, If tomorrow the bank ask the seller to provide some documents which he is unable to provide then the registration and stamp duty fees will which is a substantial amount will become sunk cost(?).Is it so or can a cancellation of sale deed happens and the cost can be recovered.Thanks in advance.