The following are the documents that need to be checked while purchasing a flat or apartment:
1. Title Deed or Mother Deed or Parent document of the property in which the flat or apartment has been built or about to be constructed. The land owner should have complete rights to sell the property. If he has any minor children and the land is ancestral property then you may face problems in the future. So, ensure that the land owner gives a no-objection certificate for sale of said property on behalf of the minor kids.
2. Property Tax paid receipts for atleast previous 15 years for the land on which the apartment is built to ensure that property taxes have been paid till date.
3. Government approved Building Plan for building the apartment. If the apartment is already constructed check if they have built as per the plan as normally they deviate a lot and construct extra flats on terrace without approval which may create problems in future. Check that whether they have left adequate space between the apartment building and the fencing wall.
5. Commencement Certificate given by the Municipal Corporation if the construction has not begun yet or if the building is in the initial stages of construction. This contains all the permissions given to the builder for construction.
6. Completion Certificate issued by the Municipal Corporation if the construction is already completed to ensure that building is constructed according to the approved plan.
7. Sale agreement between the developer and buyer of the flat.
8. Agreement of Construction to be checked whether all the things promised verbally are included in the agreement by the developer.
8. No Encumbrance Certificate issued by concerned Sub-Registrar to ensure the property has not been mortgaged as security for any loan.
9. No-objection certificate by the land owner for change of name in Electricity Bill.
10. Occupation Certificate issued by Municipal Corporation. This is to ensure that you have legal Electrical Connection, Water Supply, Sewage Connection, etc.
Engage a lawyer to verify that all the above documents are in order as the few thousands you may spend on legal verification will save you of any trouble and it is worth it.
To know more about the things to note while buying a flat check this article:
20 things to note while buying a flat