Dear Sir,
Hope you are doing well !!
As you have already invested the amount in new property there will be no further tax liabilities on you.
There is no requirement to invest the money in bonds.
There will a long term capital gain of Rs.12.5 lakhs.
It is calculated as below:
Sale consideration -Indexed COA= (Rs 21 lakh- Rs 8 lakh-.50 lakh)= Rs. 12.50 Lakh.
As mentioned earlier,
As you have already invested the amount in new property there will be no further tax liabilities on you.
However, the bonds should be bought within 6 months of the sale of the asset.
In your case, there is no requirement to invest the money in bonds.