Please remember that a right is also a capital asset.If you have purchase a right by paying some amount and later sell the right to someone and make a profit,it will constitute taxable capital gain.There is no question of unaccounted money.As the land is in India,so you will be taxed on this capital gain even if you are an NRI,but if you have no taxable income other than this,the basic exemption of rs 1,00,000 (Rs 1,10,000 from current financial year) may be deducted from the gain and you have to pay the tax on the balance.
