Subject to EPA's oversight, state and local permitting agencies generally administer NSR and operate under one of two arrangements. Under the first arrangement, state and local agencies receive "delegated authority" from EPA under which they implement EPA's NSR regulations. Under the second arrangement, states and localities are also responsible for administering NSR, but instead of implementing EPA's NSR regulations, state and local agencies develop plans, known as state implementation plans, that regulate the construction and modification of stationary sources.