Dumping occurs when
a foreign country pegs its currency at a certain trade value by manipulating markets.
a foreign country pegs its currency to a precious material such as gold, then floods the market with gold bullion.
foreign producers intentionally sell products in a foreign market at prices cheaper than it costs to make and ship.
foreign producers put up protective tariffs against a specific country while increasing existing exports to that country.
a country stops producing a product due to harmful negative externalities and instead produces the product in a foreign land so as to avoid polluting its own land.