The US is the only country in the developed world that hasn't ratified the Basel Convention [0] and the US exports close to a billion tons of plastic waste to other countries per year [1]. The trash you see building up in third world countries is in large part from the United States, not from those countries themselves.

[0] https://en.wikipedia.org/wiki/Basel_Convention

[1] https://www.invw.org/2022/04/18/rich-countries-are-illegally...