The Tribal Minor New Source Review (NSR) program applies to new and modified small sources and minor modifications at large sources in Indian country, as well as major sources proposing to construct in areas of Indian country that are nonattainment. The program is implemented through issuance of preconstruction permits. A general permit or permit by rule may be written to address a single emissions unit, a group of the same type of emissions units, or an entire category of minor sources. General permits and permits by rule offer a cost-effective means of issuing preconstruction permits and provide a quicker and simpler alternative mechanism for permitting minor sources than the site-specific permitting process while providing the same level of public health protection. This action extends the deadline for true minor sources in the oil and natural gas sector to receive minor source NSR permits.