; (bb) objective; and (cc) non-discriminatory. (ii) Engineering standards; aesthetic requirements A State or local government or instrumentality thereof may regulate the placement, construction, and modification of small personal wireless service facilities for reasons of objective and reasonable— (I) structural engineering standards based on generally applicable codes; (II) safety requirements; or (III) aesthetic or concealment requirements. (iii) Timeframes (I) In general A State or local government or instrumentality thereof shall act on a complete request for authorization to place, construct, or modify a small personal wireless service facility not later than— (aa) (AA) for collocation of a small personal wireless service facility, 60 days after the date on which the complete request is filed, except as provided in item (bb); or (BB) for any other action relating to a small personal wireless service facility, 90 days after the date on which the complete request is filed, except as provided in item (cc); (bb) for collocation of a small personal wireless service facility, if the State or the area under the jurisdiction of the local government has a population of fewer than 50,000 people— (AA) 90 days after the date on which the complete request is filed, if during the 30-day period ending on that date of filing, the applicable wireless service provider filed fewer than 50 requests for collocation of a small personal wireless service facility with the State or local government or instrumentality thereof; or (BB) 120 days after the date on which the complete request is filed, if during the 30-day period ending on that date of filing, the applicable wireless service provider filed not fewer than 50 requests for collocation of a small personal wireless service facility with the State or local government or instrumentality thereof