17.Article 9 provides the Department with a power to decline to determine any planning application or consent deemed to be the same or substantially the same as another application for the same site within the preceding two years. The provisions apply where the Department has refused a similar application under Article 31 of the Planning (Northern Ireland) Order 1991 or has refused more than one similar application and there has been no appeal to the Planning Appeals Commission; or where the Planning Appeals Commission has dismissed an appeal for a similar proposal and there has been no material change in circumstances (Repeat Applications). In addition, the Department may decline to determine an application if the Department thinks that it is similar or substantially similar to another application which has not been finally determined or is still under consideration by the Planning Appeals Commission (Twin Tracked Applications).