If I were to make a sustainable city I would focus on the means of transportation, generating power, and material production.  People would get around by bike, electric cars, and walking. To generate power, my city would use renewable resources such as sunlight, wind, and geothermal energy to power the city. Production of plastic would be reduced and we would only kill animals when needed and we would use all the different parts for different things. Altogether, my sustainable city would thrive off of nature's energy and its animals, making the CO2 concentration less.

I also believe that the most important factors in making a sustainable city would be the transportation, production, and using renewable energy sources. Most  CO2 emissions that contribute to the Greenhouse Effect come from factories and cars, which in this city would be environmentally friendly so to not emit as much carbon dioxide as we do now. By using energy sources such as windmills and solar panels, a city could reduce its emissions even more. You could also form a waste system in houses that would ensure a sustainable way waste can be recycled or composted.