A team of German-Swiss researchers has found that microscopic particles of plastic are falling out of the sky with snow in the Arctic.

Researchers collected snow samples from the Svalbard islands using a low-tech method - a dessert spoon and a flask. They found more than 10,000 of them per litre of melted snow.

The BBC's environment analyst Roger Harrabin has been looking in to what causes it.

Read more: Plastic particles falling out of sky with snow in Arctic