1. Air quality – The higher the population in a city the higher the chances of reduced air quality due to increase per capita emissions.
2. Water usage – The higher the population density in a city, the harder it is to supply adequate clean water to everybody and the water quality may begin to drop
3. Waste management- Pollution begins to become a problem when the population in a city goes beyond its carrying capacity.
4. Land use – Urban sprawl becomes a problem when a high proportion of the city’s population is squeezed in a small portions of land