According to a report in The Wall Street Journal, China and Indonesia are the top sources of plastic bottles, bags and other rubbish clogging up global sea lanes. Both nations account for more than a third of plastic detritus in global waters.
8.8 million metric tons of mismanaged plastic waste came from China, and 3.53 million metric tons of it ending up in the ocean. 3.2 million metric tons of mismanaged plastic waste came from Indonesia and it's 1.29 million metric tons became plastic marine debris.
The United States is also polluting oceans with plastic, but at a much lower level than China. 0.11 million metric tons of waterborne plastic garbage comes from the United States. This data was generated in 2010.
Image source: https://www.statista.com/chart/12211/the-countries-polluting-the-oceans-the-most/
Image license: CC-BY-ND