Cap - and - trade systems that have been implemented include the environmental protection agency ' s scheme for trading sulfur dioxide emission permits to limit acid rain and new zealand ' s reduction of overfishing by individual transferable fish - catch quotas 限量管制与交易系统目前已开始实施,例如美国环保署,为了减少酸雨而制定了可买卖的二氧化硫排放执照;另外,纽西兰为了抑制过渔,也设立了可转移的捕鱼额度。