### Question
How does the law define maintenance area?


### Answer
Under *23 U.S.C. § 101*, **maintenance area** is defined as:

> an area that was designated as an air quality nonattainment area, but was later redesignated by the Administrator of the Environmental Protection Agency as an air quality attainment area, under section 107(d) of the Clean Air Act (42 U.S.C. 7407(d))

#### Citation:
  - *23 U.S.C. § 101*
  - Heading: **CHAPTER 1-FEDERAL-AID HIGHWAYS**

