Pollution is the resource that represents the majority of waste products that a Culture provides. These products are the leftovers from industry and food consumptions, as well as by-products from the creation of certain processes and weapons, that your Culture simply cannot find a use for. This resource, in large amounts, will have a negative impact on any population in the same area as it if it is not stored in specialised depots (landfill dumps being a prime example). The only alternatives to safe storage of pollution is to move it elsewhere or to put up with its debilitating effects.