Buying private flat in sra building

That is great haa,..... thanks for informing.... 

Collect all relevant documents like copy of such sale deed, permission for construction, etc., and establish contact with earlier buyers and learn whether any finances were obtained for such construction from financial institutions and the progress of construction, and the report from earlier contracts executed by the same builder and his market reputation, then it is deemed that you have taken precautions in investing hard-earned money in residence.

Check whether there is an embargo on the sale of SRA flats in Mumbai. Usually there is. 

What do you mean by the term "SRA" used by you?

Verify marketable title of the property \.

It is advisable to consult and engage a local prudent lawyer for better appreciation of facts/ documents, professional guidance and necessary proceeding.

As a precautions, Before making any large down payment i have 1st applied for a bank loan.  I feel if my bank loan is approved, bank will do all the due diligence of the project before passing loan. Builder has completed projects in the location.