Towns grew into cities because of population increases after the industrial revolution occurred. Growth was unplanned and haphazard, straining infrastructure. The years between 1900 and 1913 saw interest in reform, design, beautification, and city clean-up. Between 1913 and 1929, city planning was formalized, and supporting organizations including chambers of commerce, City Beautiful and city planning commissions were formed. Regulations like zoning ordinances, city plans and studies, and subdivision regulations were created.