The Environmental Protection Agency (EPA) is approving a state implementation plan (SIP) revision submitted by the Commonwealth of Pennsylvania. The SIP revision demonstrates that Pennsylvania's existing I/M program in the Philadelphia nonattainment area meets applicable requirements for a Basic I/M program. The EPA is approving this SIP revision to the Pennsylvania SIP in accordance with the requirements of the Clean Air Act (CAA). [ ] CAA requirements for a Moderate ozone nonattainment area include, amongst other measures, a Basic vehicle I/M program. [ ] Requirements for a Basic I/M program are further articulated in the EPA's I/M Rule at 40 Code of Federal Regulations (CFR) part 51, subpart S.[ ] Federal performance standards [ ] for a Basic I/M program are outlined in 40 CFR 51.352.