Dear Sir,
Hope you are doing well !!
Section 49(1) Of Income Tax Act says that “Where the capital asset became the property of the assessee by succession, inheritance etc . then the cost of acquisition of the asset shall be deemed to be the cost for which the previous owner of the property acquired it, as increased by the cost of any improvement of the assets incurred or borne by the previous owner or the assessee, as the case may be.
Also, you can index the cost of acquisition according to the CII of the property for FY 2000-2001.
The CII is computed using 2000-01 as the base year. This implies that purchases prior to the year 2000 will use 100 as the CII value for calculating the indexed cost.
Here is how the indexation is done.
Indexed Cost of acquisition for the purpose of capital gains = Cost of acquisition of previous owner x [Cost inflation index (CII) of the year of transfer] ÷ [Cost of inflation Index (CII) of the year in which purchased by previous owner]