It's imprecise in that it refers to pollution that is harmful to human health as if it is the only type of pollution. It says right at the bottom of the article

It's imprecise in that it refers to pollution that is harmful to human health as if it is the only type of pollution. It says right at the bottom of the article that shipping as a whole is responsible for only 3.5 to 4 percent of climate change emissions. The shipping industry needs to get its act together too but it isn't _that_ significant when it comes to climate change. In terms of sulphur based pollutants it's pretty horrifying, though.