California Code, Health and Safety Code - HSC § 40930

(a) Each district that has adopted a plan pursuant to this chapter shall, on or before January 31 of each year, prepare and submit to the state board a report identifying the number of days during the preceding calendar year that air quality in the district violated each state ambient air quality standard for which the district's status is nonattainment.

(b) For any pollutant for which the report indicates that the applicable state ambient air quality standard was not violated during more than three days during the calendar year at any one or more monitoring locations within the district, the district shall not adopt any new or more stringent control measure until after preparation, and approval by the district board, of an analysis that does all of the following:

(c) The state board shall review the district analyses prepared pursuant to subdivision (b) to ensure expeditious progress towards attainment in both the district that prepared the analysis and any downwind district and to ensure that any resulting action of the district that prepared the analysis does not adversely affect any downwind district.