Capital gain tax under section 37(1A) is levied on the difference between the deal price and the purchase price of the property. Such capital gain tax on immovable property cannot be collected by the registration authorities. So, when you sell property, you need to pay the capital gain tax yourself when you file your income tax return. For instance, if you sell property between July 2016 and June 2017, when you file your income tax return for the 2017 tax year, you'll settle the capital gain tax after accounting for the advance tax you paid under section 236C.