Pollution

Pollution is a negative effect on the city that can cause sickness, death, and abandonment. Pollution is usually generated through industrial zones, garbage, and some types of power plants.

Pollution can take on the form of ground pollution, water pollution, and noise pollution. Ground pollution is generated through industrial buildings and other buildings that produce unhealthy atmospheric condition. Water pollution is generated through sewage produced by buildings and sent into the water ways. Noise pollution is generated through loud frequencies such as wind turbines, traffic, and areas that produce too much sound. An example of noise pollution is the one produced by an airport,  although sometimes other buildings produce pollution.

The Eden Project will start wiping out all pollution except noise pollution.

Land Pollution
Factories, higher level generates less pollution.

Some Power plants like Coal Power Plants, Oil power plants etc.

Any Water Tower placed near the pollution radus will have contaminated water

Water Pollution
Water drain pipes and Water treatment plants placed upstream to where a Water Pumping plant gets water.

Noise Pollution
Link for the article: https://skylines.fandom.com/wiki/Noise_pollution?so=search

For a quick thing, noise pollution comes from commercial buildings and many more. Unique Buildings and Monuments also generate them. Roads with heavy traffic & highways produces a lot. Avoid these buildings near residential since they can be really sick. Noise Pollution decreases land value.