Closing capital gain account before time

Capital gain account is only for temporarily parking of funds before made investments in the purchase/construction of house property. So, if you close the account you have to obtain a certificate from AO, who in turn adjust the capital gains tax and order for release of the balance.

The AO do not allow to withdraw money before the completion of 3 year tenure.

There are two types of accounts viz saving and time deposit.

You can withdraw from your saving-capital gain account when you are required to spend on purchase of property. If you want to close the account, assessing officer needs to be informed and show that you have secured a property to save tax, otherwise the whole amount will become taxable.

If you have opted for time deposit-capital gain account, then you won't be able to withdrawn before expiry of the deposit. 

Check what type of account do you have.