Interior of a large sanitary sewer viewed from an access manhole. In the developed world, sewers are pipes from buildings to one or more levels of larger underground trunk mains, which transport the sewage to sewage treatment facilities.
Free trade is a policy followed by some international markets in which countries' governments do not restrict imports from, or exports to, other countries. Free trade is exemplified by the European Economic Area and the North American Free Trade Agreement, which have established open markets. Most nations are today members of the World Trade Organization (WTO) multilateral trade agreements.
free trade - international trade free of government interference trade - the commercial exchange (buying and selling on domestic or international markets) of goods and services; Venice was an important center of trade with the East; they are accused of conspiring to constrain trade