How to fix air pollution in Cities Skylines 2 Noise pollution: caused by nearly anything, including large roads, schools, any non-residential zone, public transport stations… Noise pollution spreads in a small radius around the source, and the severity depends on the type of building or zone.Water pollution in a river or sea follows the dominant water flow, so the pollution spreads downstream of the source. Water pollution: typically caused by your sewage, but in the case of groundwater pollution, it can also be the result of a dirty building or industry placed on top of the groundwater deposit.Naturally, ground pollution stays in one place, unaffected by wind direction. Ground pollution: like air pollution, this mostly occurs below industrial zones and polluting buildings, where it gets worse over time.It’s affected by wind, thus spreading the pollution to areas downwind of the source. Air pollution: caused by industrial zones and dirty buildings such as coal power plants and garbage incineration plants.Let’s take a look at the types of Cities Skylines 2 pollution and their main causes: