The California Air Basins layer is a polygon shapefile coverage representing the 15 California air basins, as defined in state statute and regulation. This data layer shows the air basin boundaries and their names, as of March 2004. Air Basins are designated pursuant to California statute and regulation. See the California Health and Safety Code, Section 39606 et seq. and California Code of Regulations, Title 17, Section 60100 et seq.Air Basins identify regions of similar meteorological and geographic conditions and consideration for political boundary lines, and are related to air pollution and its transport.