Dumping occurs when goods are exported at a price lower than their normal value. Generally, this results in goods being sold in another country for less than their price in the original market or at less than production costs. This may mean that domestically produced goods are more expensive to buy than the imported and dumped goods, undermining the local economy and production sectors. To prevent this, a non-tariff barrier may be implemented, called an anti-dumping duty. This is a duty levied at a value equal to the difference between the goods' export price and their normal value.
Dumping is also the term informally used to describe what happens when a product is declared unfit for sale but is then sold at below cost. This can lead to goods banned in the exporting country because they are dangerous products being “dumped” on another (often very much poorer) country.