Four years ago, the UN's International Maritime Organization decided to ban passenger ships from dumping sewage into the sea, starting in 2016.
But at a meeting this week in Germany, Poland and Russia want to postpone the ban saying, several Baltic ports are unable to accommodate the large amounts of sewage cruise ships must unload.
Mattias Rust, who is responsible for maritime issues at the environmental group WWF here in Sweden, said the practice is terrible for the sea's ecosystem and disgusting.
"Waste water is like a smörgåsbord for algae," he told Swedish Radio News. "How do you think it would look if we had a hotel dumping out their sewage directly into a grove of trees?"
In Stockholm's port, ships are able to empty their sewage tanks, and it is becoming more common that they do so, according to Henrik Ahlqvist, in charge of marketing at the habor.
He said this year the city has received more than 45,000 cubic meters of waste and gray water from cruise ships.