What if we banned the internal combustion engine, then discovered that it was still hot in the summer in cities?

More frequent, more intense heat waves in store for New York — Science Blog

Data collected by City College’s New York City Meteorological Network (NYCMetNet), indicate that during the first July heat wave overnight low temperatures ran 10 to 15 degrees (Fahrenheit) higher in Manhattan than in Long Island or in western New Jersey, while daytime highs were roughly the same.
...
Another research thrust is the role played by aerosols, which are fine particles of solids or liquids in the atmosphere. Urban areas tend to generate aerosols, and the resulting humidity could modify precipitation patterns by interacting with clouds and affecting the energy balance, Professor Gonzalez explained. “The presence of pollution could increase or diminish rainfall. It could change the frequency and severity of storms, as well.”