Smoke spewing from China’s factories is wafting across the Sea of Japan and coating Japan’s trees with a layer of contaminants similar to the acid rain that’s ruined forests in Europe. “Hana-boro”–the little crystals of ice that cling to Japan’s tree branches in winter””used to be sparkling white. Now, a noxious blend of vehicle exhaust and pollution from China’s coal-burning power plants has turned the hana-boro brown, according to Japanese news service Asahi Shimbun.

And that’s just one kind of “transboundary pollutant” that’s arriving uninvited from China and fouling Japan’s environment. Untreated sewage effluent from China’s cities is wreaking havoc with marine life in the Sea of Japan, promoting the growth of microorganisms that have led to an explosion of huge Echizen jellyfish. These “tentacled giants” first began appearing off the coast of Japan in 2002, and are a terrible problem for fishermen, causing “extensive damage to nets and to hauls themselves,” Asahi Shimbun reports.

Last November, researchers from Japan, China and South Korea determined that the Echizen jellyfish “have been showing up en masse in Jiangsu province, around the estuary of the Yangtze where it flows into the East China Sea, since 1997.” But China insists there’s no correlation between its own explosive growth and the proliferation of the giant jellyfish. The Japanese aren’t buying it, but as long as the rest of us keep buying Chinese consumer goods without demanding that China cleans up its act, Japan’s gonna be stuck with jellyfish-clogged seas and smog-coated trees.