Interpol has announced that more than 1.5 million tonnes of illegal waste were seized in June in the biggest ever global clampdown that involved 43 police forces.

More than 300 people and over 200 companies were cited for violations over disposal of waste, much of which ends up polluting the sea or land and constituting a health hazard.

Most of the waste seized was metal or electronic, and often related to the car industry.

Asia and Africa were the main destinations for waste illegally exported from Europe and North America for dumping or processing, with trafficking also occurring between countries in Europe.

Interpol says that of the 275 million tonnes of plastic waste generated in 2010, up to 12.7 million tonnes were illegally dumped into the ocean.

It said that waste crime is seen as a low-risk, high-reward business for organised networks which exploit differences in legislation between countries and regions, as well as weak enforcement systems.

"It shows what can be accomplished when countries work together to detect, disrupt and deter pollution crime," said Joseph Poux of the US Department of Justice.

The month-long operation in June, called 30 Days of Action, was aimed at giving a warning to criminals who specialise in this kind of traffic, he said.

"The organised criminal groups involved in illicit waste trafficking should be warned that they will be caught," he said in a statement issued by the Lyon-based Interpol.

"Waste crime is a worldwide concern: of the 275 million tonnes of plastic waste generated in 2010, up to 12.7 million tonnes were illegally dumped into the ocean," said Interpol.

"When hazardous waste is improperly disposed, it contaminates the water, soil and air, threatening global health and safety."