As the property was purchased before 2001, cost of acquisition can be actual cost incurred or stamp duty value (i.e. SDV) of the property as on 01.04.2001 whichever is higher. To get the SDV as on 01.04.2001 and of the current date, you can obtain valuation report from the govt. approved valuer. I think in Delhi, SDV is available from 2007.
Benefit of indexation is available to resident only on sale of immovable on or after 23.07.2024
Any capital expenditure incurred post 01.04.2001 can be claimed as cost of improvement
Transfer expenses incurred wholly and exclusively for the purpose of transfer are allowed as deduction from the full value of sale consideration
There are many other points of consideration
For detailed discussion you may opt for phone consultation