The documents that should be checked before buying a flat are- Sale Deed, Mother Deed, Building approval plan, Commencement Certificate (For under construction property), Conversion Certificate (Agricultural to Non-agricultural land), Khata Certificate, Khata Extract, Encumbrance Certificate, Betterment charges receipt, Power of Attorney(POA), Latest tax paid receipt, Completion Certificate (for a constructed property), Occupancy Certificate (for a constructed property).