Dear Sir,
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1 & 2. It is advisable to get the FMV/ valuation of the land as on 01.04.2001 done from the registered valuer.
Government-approved valuers follow a standard process for the valuation and provide a detailed report.
“Assumptions of any type for consideration of value shall not be entertained by the income tax department. In case of any enquiry, the department will consider the value stated in the valuation report from a registered valuer,"
3. You can take the benefit of indexation on cost of improvements subject to sufficient proofs.
-However, in absence of proofs, you can get valuation report from the Engineer/Approved valuer for estimated cost of construction/ improvements during the years.
-Also you can claim Expenditure in connection with transfer/sale: It includes brokerage charges, registry charges or other expenses made on the asset sale
It is advisable to take a phone consultation for detailed discussion.