Drone footage shows vast amounts of pumice pebbles, spewed out months ago by an undersea volcano, clogging up a fishing port in Kagoshima prefecture, in southern Japan. The pumice has so far affected 19 ports in Kagoshima, and 11 on Okinawa, putting hundreds of fishing boats out of action and damaging the tourism industry.

• Japan ports swamped by pumice spewed from undersea volcano