1) you should contain a local lawyer ask him to carry out 30 years title search before purchase of property.
2) if property has OC issued that would imply house has been completed as per sanctioned plans
3)you can buy property ifd title is clear and marketable
4) apply for bank loan for purchase . let bank do due diligence
5) if at all you buy property sale deed must contain an indemnity clause wherein seller indemnifies you against any claims if any made in respect of the property
6) also file RTI with BDA as to whether property is proposed to be acquired by BDA