The containers were intended to transport used mattresses, rugs and rugs, but also contained hospital waste, officials said.
The contents of the container were believed to include used mattresses, carpeting and rugs, but it also contained hospital waste, officials said.
“The sender had agreed to take back these 21 containers,” customs spokesman Sunil Jayaratne told AFP on Sunday. “We are working to obtain compensation from the people responsible for bringing the containers into the country.”
Customs did not disclose the type of hospital waste, but previous illegally imported containers included rags, bandages and body parts from morgues, officials said.
Another 242 UK containers, which the government said contained illegal waste in violation of international law, remain abandoned in the same port and in a free trade zone outside Colombo. They arrived in 2017 and 2018.
The government is currently engaged in legal action against the shipper to have the 242 containers removed from the country.
A Sri Lankan investigation last year into nearly 3,000 tonnes of illegally imported hazardous waste found that the importer reshipped around 180 tonnes to India and Dubai in 2017 and 2018.
In recent years, several Asian countries have refused to be treated as the dumping ground for the rich world and have returned containers of waste from overseas shores.