quota

In international trade, a limitation on the amount of a commodity that may be exported, imported, or produced. Restrictions may be imposed forcibly or voluntarily.

The justification of quotas include protection of a home industry from an influx of cheap goods, prevention of a heavy outflow of goods (usually raw materials) because there are insufficient numbers to meet domestic demand, allowance for a new industry to develop before it is exposed to competition, or prevention of a decline in the world price of a particular commodity.

The European Union's Common Agricultural Policy has introduced quotas to limit the production of milk because rising herd yields and a trend towards a healthier low-fat diet have led to overproduction. Dairy farmers will not be paid for any milk produced above a set limit.