Due to concerns about the adverse impact of washing water on the marine environment, the regulatory provisions on open desulfurization units at home and abroad are becoming increasingly stringent. Generally speaking, open desulfurization units are prohibited or will become mainstream, but there are variables. Some countries prohibit the use of open desulfurization units (prohibit the discharge of washing water), including China's emission control area, the United States (Connecticut, California), Singapore, the United Arab Emirates, Pakistan Nama, Norway (within the world heritage "fjords"), Germany, Belgium, Lithuania, Latvia, Ireland and other regions and ports. However, there are also countries or regions that allow ships to use open type desulfurization devices, such as Japan, South Africa, Iceland, Turkey. Meanwhile, Australia, Hong Kong, and Taiwan need to apply for equivalent approval, which can also be equivalent to open type desulfurization devices. From the perspective of regulatory policies and IMO guidelines of various countries, the list of countries that prohibit the open desulfurization device is mostly in the world, and the list of countries that prohibit it may be further increased. However, the current global IMO MARPOL convention still permits the use of EGCS and the discharge of washing water. The EU, the United States (Hawaii, etc.) and China (except for coastal ports) are also implementing relevant IMO regulations in addition to the waters with special regulations, It is also allowed to discharge the washing water, and there is still uncertainty in the preliminary judgment that IMO completely prohibits the use of open scrubbers.