Having seen the trash coming down several of these rivers in person, everything I could identify seemed to be of local origin. I certainly didn't see non-local languages written on plastic bottles, for example.
It's just fashionable to blame everything on the West.
The East isn't any different.
So absolutely nothing was coming from upstream? Or, at least, it seemed local trash was dominating the area and perhaps staying put?
Perhaps when it gets too full of local trash, some of it gets moved to the ocean?
Why would that change anything? This is local trash in the rivers not recycling.