State Significant Infrastructure (SSI)  
  A development declared under Part 5.1 of the Environmental Planning and Assessment Act 1979 (NSW) to be State Significant Infrastructure. A State Environmental Planning Policy is the most common way in which development may be declared as SSI. It includes projects such as railways, road, ports and telecommunications systems. SSI projects are subject to a separate approval process. The application must be placed on public exhibition and be accompanied by an Environmental Impact Statement. Ministerial approval is required for all SSI projects.