Images of Hong Kong beaches covered in rubbish have become a common sight on social media.

In a rare statement, the Environmental Protection Department recently said, “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.”

Rattan beach mats are left behind with plastic bottles, beer cans and packets of food arranged around spots where people once sat like a murder-scene chalk outline.