There are a number of environmental issues in Bhutan. Among Bhutan's most pressing issues are traditional firewood collection, crop and flock protection, and waste disposal, as well as modern concerns such as industrial pollution, wildlife conservation, and climate change that threaten Bhutan's population and biodiversity. Land and water use have also become matters of environmental concern in both rural and urban settings. In addition to these general issues, others such as landfill availability and air and noise pollution are particularly prevalent in relatively urbanized and industrialized areas of Bhutan. In many cases, the least financially and politically empowered find themselves the most affected by environmental issues. Through 2011, Bhutan experienced accelerated economic activities which pressured natural resources such as land, air, and water. Development activities increased urbanization, industrialization, mining and quarrying, agriculture, and solid waste management projects. Land degradation, biodiversity and habitat loss, high fuel-wood consumption, and human-wildlife conflicts are some of Bhutan's environmental challenges. Notwithstanding these problems, Bhutan remains overall carbon-neutral, and a net sink for greenhouse gases. Within the Bhutanese government, the independent National Environment Commission (NEC) and Bhutan Trust Fund, as well as the executive Ministries of Health (for chemical and radioactive waste), Economic Affairs, and Agriculture and Forests (Department of Forestry Services) are tasked with addressing environmental issues. Waste disposal issues often fall to local governments, Bhutan's dzongkhags and thromdes. Non-governmental agencies active in addressing environmental issues in Bhutan are the Royal Society for the Protection of Nature (RSPN), the only domestic environmental NGO, and the World Wildlife Fund (WWF). National issues To address environmental issues, the government of Bhutan has banned certain practices with varying success. Tsheri agriculture, especially prevalent among Sharchops and Lhotshampa, is a practice by which land is cleared and farmed intensively until it becomes unproductive and is thereafter let fallow. Because it is particularly environmentally harmful, the practice has been banned by the government since 1969, however it continues today. In the mid-1980s, it accounted for 32 percent of the agricultural land use and about 3 percent of the total land use. In the early 1990s, Bhutan imposed a ban on timber exports, though domestic timber harvesting remains heavily regulated under a network of foresters and road checkpoints. In April 1999, Bhutan also prohibited plastic bags nationwide. The ban on plastic bags, however, has proven a daunting challenge in implementation and enforcement because of the practicality of lightweight airtight storage and