Emission control areas have different naming depending on the regulator who define them. They are generally called ECA. However the rules to apply when sailing in ECA can change from one area to another because the regulator is different, e.g. the IMO (International Maritime Organization) or the local governments.
ECAs are located along the coasts on a distance that can reach 200 nautic miles, or are defined on a particular geographical area. The current ECA are located in Northern Europe, along with the American coasts (including American Islands and Territories), and in the estuaries of the great Chinese rivers.