Section 1 reiterates the sustainable duty contained in the Northern Ireland (Miscellaneous Provisions) Act 2006, which places a duty on all public authorities in respect of sustainable development. Section 25 of that Act states that a public authority must, in exercising its functions, act in the way it considers best calculated to contribute to the achievement of sustainable development in Northern Ireland, except to the extent that it considers that any such action is not reasonably practicable in all the circumstances of the case.