Recovery of tax: central tax officer may recover unpaid GST and credit amounts to union territory account proportionately. Section 13 empowers the proper officer of central tax to recover unpaid tax, interest or penalty by treating it as an arrear of central tax and to credit amounts recovered to the Government under the appropriate head of union territory tax; if the amount recovered is less than the total due under this Act and the Central Goods and Services Tax Act, the credit must be apportioned between union territory tax and central tax in proportion to the respective amounts due.