Any restriction, charge, or policy other than a tariff, that limits access of imported goods. Examples of nontariff barriers include quantitative restrictions, mainly import quotas and embargoes; import licenses; exchange controls; state trading enterprises; bilateral agreements; and certain rules and regulations on health, safety, and sanitation. The Uruguay Round Agreement on Agriculture requires conversion of NTBs to bound tariffs and tariff-rate quotas, and that sanitary and phytosanitary measures be based on sound science.