Have you found the FMV of land on 01.4.01 and then calculated capital gain.
Yours is a different situation as property was registered in June and final payment was also done in 2017 before one year and only possession was received within one year so it would be very difficult to show a nexus between such sale and purchase but there are case laws where date of possession has been considered as date of purchase and exemption has been claimed.
So you may try based on the case law but it's a tricky situation.
Hope you find the information helpful if you do please rate it 5 and provide your valuable feedback for my improvement.
Thank you