Foreign manufacturers engage in the practice of “dumping” when they export products to the US or other nations at prices below the established domestic market price or when they ship excessive quantities of products that cannot be explained by normal market competition.
World Trade Organization (WTO) members, including the US. and the EU, may take action to offset injurious dumping of products imported from another member under Article VI of the General Agreement on Tariffs and Trade.
For example, for the US, under the Department of Commerce's International Trade Administration regulations, US domestic firms may file antidumping petitions claiming that imported goods are priced at "less than fair value." The International Trade Commission may find there is “injury” to the US domestic industry and impose “antidumping” duties on imported goods at a percentage rate calculated to counteract the dumping margin. The US Trade Representative monitors trading partners' activities, enforces US rights under trade agreements, and negotiates and signs trade agreements that advance the President's trade policy.
Measures that these US takes are published in the Federal Register and this can be viewed here: https://www.federalregister.gov/international-trade-anti-dumping-
The EU takes the same stance: A non-EU company is 'dumping' if it exports a product to the EU at a price lower than the normal value of the product. The normal value is either product's price as sold on the home market of the non-EU company, or a price based on the cost of production and profit. In the EU, it is the European Commission is responsible for investigating dumping claims and imposing measures. It opens an investigation after receiving a complaint from the European producers of the product concerned.
Anti-dumping measures can be put on imports of specific products if the countries anti-dumping investigation justifies it. These measures are usually in the form of an 'ad valorem' duty. Other measures that can be applied include a fixed or specific amount of duty or, in some cases, a minimum import price. There are also price undertakings which may also be accepted instead of anti-dumping duties. This is where the exporter agrees not sell products in the EU at prices below a minimum amount.
If the authorities agree to an undertaking then the anti-dumping duties will not be collected on those imports. The authorities are not obliged to accept an offer of an undertaking.