What happens when if pollution gets in the water?

Obviously, pollution is harmful towards living things. One example of pollution is oil spill. The oil floats on water and the fish that are coming up to the surface of the water to get air will suffocate. So, if the marine life dies just because of oil spill, most of the animals in the sea will be extinct. Just imagine eating fish and chips with just the chips. The pollution in the water MAY also affect the air around it, suffocating land animals including humans.