A number of councils in Wales are sending recycling waste to be processed to countries such as China and India, it has emerged.
Some councils are shipping plastic, cardboard and cans abroad
Plaid Cymru said it wanted recycling policies reviewed after uncovering the information.
Cardiff, Denbighshire, Flintshire, Pembrokeshire, Powys and Swansea admit shipping waste overseas.
The Welsh Local Government Association says sometimes it is not viable to process all the waste in the UK.
Plaid AM Leanne Wood said: "It is clear that a not insignificant amount of Wales' kerbside recycling waste ends up being processed in countries such as China and India.
"People who diligently recycle their waste do not expect it to be transported that far."
COUNCILS SENDING WASTE OUTSIDE EUROPE
Cardiff: Cardboard, plastic - Indonesia/China
Denbighshire: Plastic - China
Flintshire: Plastic film - China
Monmouthshire:: Plastic - China
Pembrokeshire: Cardboard, plastic bags, cans - China/India
Powys: Mixed cans - China
Swansea: Cardboard, plastic, mixed glass - China, Brazil and other Far East location
Source: Plaid Cymru
According to the figures obtained by the party, a further seven councils in Wales either did not know if waste they collected was being shipped abroad, or accepted it was a possibility.
Ms Wood added: "People's good intentions could be compromised by the fact that some of the waste ends up being shipped halfway around the world.
"It's hardly the most sustainable policy and grossly counter-productive."
The WLGA said local authorities strived to process green waste as close to home as possible, but sometimes that was not a viable option.
"The Welsh, UK and sometimes even the European markets are not appropriately equipped to take all the products that are collected from the kerbside," said a WLGA spokesperson.
Examples of materials being sent out of the UK include baled cardboard to Indonesia and China by Cardiff, aluminium cans sent to India by Pembrokeshire and mixed glass sent to Brazil by Swansea.
The WLGA added: "If Wales wants to become a recycling nation, then recyclate (material collected for recycling) has to be seen as a resource to be traded on the world commodities markets.
"To assist with paying for and improving collections, councils, their partners or their contractors will try to secure the best deal and get the best price possible."