In case of increase in duty, approval of Parliament required: 

If there is any increase in the duty as specified above, then the Central Government is required to place such notification in the Parliament for its approval.

Every notification insofar as it relates to increase of such duty, shall be laid before each Ho use of Parliament if it is sitting as soon as may be after the issue of the notification, and if it is not sitting within seven days of its re-assembly, and the Central Government shall seek the approval of Parliament to the notification by a resolution moved within a period of fifteen days beginning with the day on which the notification is so laid before the House of the People. If the Parliament recommends any change in the notification, then the notification shall have effect subject to such changes. However, any thing done pursuant to the notification before the recommendation by the Parliament shall be valid [Section 7(3)].