@ Anupam:
Could you please provide more details like date of purchase of flat and sale of property (presuming flat and property were 2 different assets, otherwise no indexation can be considered since it would be a STCG as it was purchased in June 2015)
Also if they were 2 different assets, was the property sold, a residential house or any other property.
If it is residential house then you can claim an exemption u/s 54.
Quantum of exemption u/s 54 will be:
If cost of new residential house >= CG, entire CG is exempt
If cost of new residential house < CG, CG exempt is to the extent of cost of new residential house
Needless to say, cost of the house could be owned and borrowed both. In the present case, cost of house is > CG, hence entire exempt.
If it is any other asset other than a residential house AND there is no residential house at the time of sale of asset, then claim exemption u/s 54F
Quantum of exemption u/s 54F will be:
If cost of new residential house is >= Net sale of the asset, entire CG is exempt
If cost of new residential house is < Net sale of the asset, CG exempt is to the extent of (LTCG x Cost of residential house) ÷ Net SaleConsideration is exempt u/s 54F
In the present case, cost of house is > net sale consideration, hence entire exempt.
Check out which is applicable to you and work accordingly