Thomas Fuller is San Francisco bureau chief for The New York Times. Josh Haner is a staff photographer for The Times based in San Francisco. Additional reporting by Alastair Boone. Map by Denise Lu. Produced by Michael Beswetherick, Morrigan McCarthy and Andrew Rossback. Additional work by Mike Puretz and Eden Weingart. Drone piloting in Mexico by Ismael González González.



Source: U.N. Report on Housing Conditions