Capital Gain Tax on Residential Property

Q1: Purchased a property in 2008-09. Registry done in 2011-12. What time period to be taken while doing indexation?

Q2: Also, paid some amount to freehold the property in 2011-12. Can this cost be treated as cost of improvement?

Q3: The above mentioned property is going to be sold in April 2021. Upto when can money be deposited into Capital Gain Account Scheme? 6 months from sale of property i.e. October 2021 or before due date of filing return i.e. July 2022 ?

Thanks & Regards