Generally denial of OC will be due to extra floor or abnormal deviation in construction violating the permitted limit.
Without OC he cannot get khatha for the constructed building, confirm if he has really got one and whether it is the genuine extract given by the authorities concerned. .
Actually OC is issued for an entire building, or a part thereof, and is not given to individual flats.
The law states that it is illegal for a building without OC to be occupied.
There are several reasons for this, including: The building is not as per the sanctioned plan, has illegal unsanctioned floors/ walls/ extensions The building is not safe to inhabit because of quality of construction, safety of stairs/ lifts, electrical safety, fire safety, airline safety, etc.
Not built as per the sanctioned plan – including plinth, setback, height, FAR. Facilities like club house, party hall, etc. need to be in the sanctioned plan. Deviation till 5% may be allowed
The building is not capable of fulfilling its mandatory role in managing its waste, sewage, water.
Builders, without fulfilling the mandatory terms of sanction and/or promises to the buyers are eager to hand over and move on to the next project. By getting people to live in the flats, they create a shield for themselves. They also escape from the delay penalty clauses that are in the agreement. - Buyers are eager to take possession of their homes. Many are not even aware of OC and what it means.
Have you verified the Katha Certificate and Extracts. It has the details of the property in a particular format with the name, size of the property, use of the property (commercial purpose, residential), annual value, when assessed last.
Have you verified Supplementary agreement / Ratification Deed (if any). To avoid any future shock on modified clauses which you might not be aware of & is not included in property documents.
However be sure that the the flats without OC cannot be issued with A khatha, without seeing the copy of the khatha and verifying its genuineness it may not be advisable to proceed with the purchase, take a legal opinion from a local lawyer before buying the property.