摘要：“Market failures” refer to situations in which the normal market forces of supply and demand fail to deliver an optimal outcome for society as a whole. Market failures commonly occur when producers and consumers do not take into account the full cost of their actions, such as pollution inflicted on third parties (environmental externalities). In such cases, too much resources are invested in polluting activities and too few in pollution abatement. Undefined or ill-defined property rights over natural resources are another cause. If anyone, without restriction, can harvest the riches of the seas, extract the resources of forests, graze animals or collect firewood on common land, or tap water freely from municipal wells, the result is often overexploitation, a phenomenon known as the “tragedy of the commons”.
"市场失灵" ，是指市场力量使得供给与需求不能为社会的整体利益提供一个最佳的效果。市场失灵常见的是，生产者和消费者没有考虑到他们行为的全部成本，如对第三方（外部环境）的污染。在这种情况下，过多的资源被投资在污染活动中，而用于减少污染治污的又太少。未定义或定义不清的自然资源的产权，是另一个原因。如果任何人，在共同的土地上，也不受任何限制，可以收获丰富的海洋资源，或提取森林资源，动物或收集柴火，或从市政水井自由地不节制地取自来水，其结果往往是过度开采，这一现象被称为"共同的悲剧" 。