I was guessing China would have the worst rivers, but that map also puts the spotlight on India. It's easy to see that general region isn't doing good. This seems like a good way stop plastics before they reach the ocean.
Like a 10 minute drive (I was not a driver) from the offices of pretty famous western companies one could see improvised disposal sites for trash; sometimes burning and people going through them and seeing what they can find.
There seemed to be way too little organized trash pickup so people just threw their trash somewhere and after a while either the government acted or people decide to burn it to get rid of it.
I assume if there is a river nearby many will take that option instead of burning it.