That's a proper grey waste dump

[Figaro]

https://www.express.co.uk/travel/cr...pollution-carnival-cruises-grey-spill-florida

 

[PeteH]

In My day. Everything, went "over the side". The clean-up started in the 60`s with the introduction of what became known as "Seaway" systems. Progressively over the years the Shipping "game" has become probably one of the least polluting transportation means. Cruise ships aside, it is the least polluting means of transporting the goods "modern" society insists on, in terms of "clean" miles per Kg of goods transported. As older vessels are scrapped, this will become even cleaner.

A modern vessel very rarely now, except by accident, or following (say) collision puts anything but clean water back into the oceans.