The WTO is headed by a Director-General. Barriers to trade are obstacles that countries impose on trade, most commonly in order to restrict imports, less commonly to curb exports.
Tariffs are the most common form of barrier.
They are taxes on imports. They place limits on quantities of imports. Administrative barriers are government regulations or procedures that have the effect of restricting imports in some way. Typical examples are regulations that impose certain safety, health or other quality standards on imports. For example, most countries require that imports of unprocessed fruits, vegetables, meat or other agricultural products be accompanied by certificates guaranteeing that they are not carrying diseases or pests.