What sale value should be considered?

For the calculation of capital gain, the sale consideration that needs to be considered is the actual sale value or consideration received at the time of transfer of the asset. In this case, as the agreement to sell was made in 2010 and the whole amount of 21 lacs was received at that time, the sale consideration for the purpose of calculating capital gain will be the same amount of 21 lacs.

@ ayush.....what about rate circle if increased after 13 yrs

Net realisable value is the cost.

Property is said to be conveyance when actual SALE deed is registered
Capital gains occur when actual transfer takes place
in above case ACTUAL transfer is in 2023 though amounts recived in 2010
Now,....capital gains amount shall be difference between amts recived or circle rate (5 percent difference allowed), which ever is higher and applying indexation
So, accordingly after considering above facts capital gain must be ascertained

Please refer Sec

In this case, sale consideration should be stamp duty value or 21 lacs, whichever is higher.

Sale consideration is always considered in case of appreciating asset on the higher side.