Just 10 rivers are carrying 90% of the plastic entering the oceans, a study has found.
Two of them are in Africa – the Nile and the Niger – while the others are in Asia: the Indus, Ganges, Amur, Mekong, Pearl, Hai he, Yellow and Yangtze.
As well as being some of the world’s longest rivers, they have big populations alongside them.
The Helmholtz Centre for Environmental Research in Leipzig, Germany, also said they tend to be in countries where waste control could be better.
:: Yangtze River, China
This was the worst offender, according to research published in the journal Environmental Science & Technology. It carries up to 1.5 million tonnes of plastic into the sea every year. In contrast, the Thames puts 18 tonnes of plastic into the ocean.
:: Hai he River, China
This waterway connects Beijing to Tianjin and the Bohai Sea. Its annual flow is only one-thirtieth the Yangtze’s, and half that of the Yellow River.
:: Yellow River, China
After the Yangtze and the Yenisei, this is the third-longest river in Asia – and the sixth-longest river system in the world. It flows through nine provinces before emptying into the Bohai Sea.
:: Mekong River – various countries
This is the second-longest river in Asia, travelling through China, Myanmar, Laos, Thailand, Cambodia and Vietnam.
:: Pearl River – China and Vietnam
Named after pearl-coloured shells that lie at the bottom of the river in the section that flows through the city of Guangzhou.
:: Indus River – China, India, Pakistan
Pakistan’s longest river. Its basin covers about 384,000 square miles of open land, of which 204,000 lie in Pakistan.
:: Ganges River – India and Bangladesh
Despite millions of Indians depending on it for their daily needs, the Ganges is considered to be the fifth most polluted river in the world. It contains human waste and industrial contaminants, but provides water to about 40% of India’s population.
:: Amur River – Russia, China
This waterway forms the border between Russia and China, and has been an important part of Chinese-Russian relations.
:: Nile River – multiple countries
Commonly regarded as the longest river in the world, its basin covers 11 countries including Egypt, Sudan, Ethiopia and Kenya.
:: Niger River – various countries
This is the principle river of western Africa, running through Guinea, Mali, Niger, Benin and Nigeria.