An estimated one billion urban residents live in informal settlements. These settlements have grown in response to rapid population growth and a lack of affordable, higher-quality alternatives. They are "informal" because they do not comply with government regulations. Historically, the official response was typically intimidation or, if they were not highly visible, neglect.
Over the last 50 years, however, many local governments and some national ones have recognized their importance in housing the majority of the low-income population and workforce, alongside numerous businesses. Consequently, they have turned toward upgrading instead.
