Sweden was facing a serious soil acidification and water eutrophication problem caused partly by emissions of nitrogen oxides (NOx) from combustion processes in transport, industry and power. In 1992, Sweden introduced a high tax on NOx emissions from large combustion sources (e.g. power plants,...

Lake Taupo is New Zealand’s largest lake, and a national icon. Its pristine waters attract visitors from round the world for a multitude of water-based recreation and sight-seeing activities. It is also important to New Zealand’s indigenous peoples. In the late 1990s, scientific...