[lmm]

Much more, yes - modern ships have been built slower, with lover rev-engines, to save fuel. And a larger ship is inherently more environmentally friendly. And even the oldest ships do far, far less environmental damage per kilogram per kilometer than cars or other road transport. Not to mention that the issues with nitrogen oxide emissions in particular (the focus of the recent scandal) are less about environmental damage and more about the danger to humans from breathing them in, which is obviously a lot more important when emissions are happening in the middle of a city rather than out on the open sea.