The Environmental Protection Agency (EPA or Agency) is determining that the Las Vegas, Nevada nonattainment area ("Las Vegas") failed to attain the 2015 ozone National Ambient Air Quality Standard (NAAQS) by the applicable attainment date. The effect of failing to attain by the applicable attainment date is that Las Vegas is being reclassified by operation of law as "Moderate" nonattainment for the 2015 ozone NAAQS on January 5, 2023, the effective date of this final rule. Accordingly, the Nevada Division of Environmental Protection (NDEP) must submit State Implementation Plan (SIP) revisions and implement controls to satisfy the statutory and regulatory requirements for Moderate areas for the 2015 ozone NAAQS according to the deadlines established in this final rule.