This time of year, many Hong Kong residents relax on the beach or splash in the waves. But this year, that’s not really possible; for the last two weeks, the beaches have been inundated with trash washing up on shore.

“Trash on the beach is nothing new in Hong Kong, but this is completely different to what we would normally see,” Gary Stokes, Southeast Asia Director of the Sea Shepherd Conservation Society tells James Griffiths at CNN. Yet, according to Stokes, most of the normal beach trash is from local sources. But labels found on much of the debris indicates it's coming from mainland China.

Locals lit up social media complaining about the problem, but little has been done to address the situation or investigate its origin. "There is a tragedy happening in Hong Kong now, and effectively a solidified 'oil spill' of trash/plastic washing up on Hong Kong's beaches," writes Doug Woodring on Facebook.

Woodrig is co-founder of a local conservation group Ocean Recovery Alliance, who released an app called Global Alert that allows locals to report trash build ups on beaches, reports Josh Horwitz at Quartz. So far, trash is covering all the beaches on Lantau Island, the largest in the municipality, and many beaches on Hong Kong Island, including Stanley Beach, which hosts the annual dragon boat races.

No one knows exactly where the trash is coming from. Stokes tells Griffiths that an unusual wind pattern or tide may be simply redirecting mainland trash that normally floats out to sea. “This could be putting the spotlight on a lot of illegal dumping that was already going on,” he says.

According to Stokes, an island called Wai Ling Ding in the Zhuhai municipality south of Hong Kong could be to blame. Stokes says a giant dump on the island is pushing trash into the sea and toward Hong Kong. “It’s pretty much like a glacier of trash that keeps sliding down the hill,” he tells Griffiths.

After weeks of keeping mum about the problem, the Hong Kong government finally made a statement about the trash this morning. Adam Wright and Kylie Knott at the South China Morning Post report that officials blame recent floods in China’s Pearl River Basin for the “plastic tide.”

“We suspect that the floods in mid-June on the mainland might have brought the refuse to the sea and then the refuse is brought to Hong Kong by the southwest monsoon wind and the sea currents,” the Hong Kong Environmental Protection Department states, also pointing to a similar trash buildup after major mainland flooding in 2005. The agency has not announced plans to address the problem.

In the meantime, locals and conservationists are taking the cleanup into their own hands. Sea Kayak Hong Kong's David Wilson tells South China Morning Post that he found several dead sea creatures, one wrapped in plastic. “It was a shock," he says. "Hong Kong has had a trash problem for a very long time—it’s in denial. We only found one spot 15 meters long that did not have rubbish.”

So far, volunteers are cleaning up some of the trash, and in September thousands of volunteers will descend on the beaches as part of the 16th Annual Hong Kong Cleanup Challenge.