Each state has its own legislation relating to apartments/flats. So you'll have to be specific which state the apartment/flat is located.
Further, in a recent judgment the Supreme Court has categorically held that parking areas cannot be sold separately. However this judgment itslef is based on the analysis and interpretation of relevant laws in Bombay, and therefore its applicability in other states is at most persuasive ( i.e it is not binding law for other states)
The views expressed above , in no manner purport to be an expert legal advice on the query riased, and you are advised to seek opinion of an expert legal advisor