Hi,
As the capital gain pertains to AY 2013-14, and you have not disclosed it in your income tax return and also did not invest the capital gain amount in any capital gain exemption scheme, so you are liable to pay capital gain tax.
To avail capital gain exemption :
1) the capital gain need to be invested with six months of the sale proceed in capital gain bonds (NHAI or REC bonds)
2) The capital gain amount can be deposit in Capital Gain Account Scheme (CGAS)within six months of sale proceeds- if there is any intention of buying or constructing the house within three years of depositing a amount in CGAS.
3) If you had bought any house with one year before the sale or within two years after the sale of plot then you can claim capital gain exemption.
if above three mentioned conditions are not fulfilling then it falls under undisclosed income and you are required to disclosed it under ( Income Declaration Scheme)IDS-2016 by filling form 1.