First and foremost, we must clean up the pollution which is created by the cities.  We should begin by taking the city spewing the most pollution then begin construction of a twin clean city as close in proximity to that city as possible.  The new city will be efficient and self-sustaining.  Beginning at the foundation which will contain underground transportation on networks(roads) which will be used for all vehicular activities needed by the city (moving, deliveries, waste disposal).  In this underground section of the city is where all garbage will flow and this garbage will be sorted by the people who choose to be homeless, in where they will have a private room with a bed and bath, which is provided by their sorting of the trash.  They may do just enough to remain in the city or they could do more, being able to earn a great deal more money.  From above, the city shall be vehicle free with the exception of trams and cycling.  All people working outside the city will park in areas outside and around the city and come in via trams, cycling, by foot or parking below where one works.  When this city has been completed then the inhabitants and workers of the previous city can begin to inhabit and commute to this new city.  The old city will then be used by the military where they will be tasked with the rejuvenation of the city into making it also self-sufficient and clean running.  The military will be available to all others from the private sectors to come with ideas and solutions in the conversion of the existing city.  This will also keep out the potential for illegal activities from entering and taking over the area.  The military will be given, at first, the bare minimal to live and must innovate to provide what is needed to retrofit the old city into the new age.  For as i say all this, here in Europe, i find some towns already starting to keep out vehicles and allow only trams, cycling and walking in the interior.

https://sites.google.com/site/archetypealgorithm/

https://archetypealgorithm.earth/