5. About 18.3% of the land area has been demarcated as protected and conserved areas. Proper management of the protected areas for biodiversity conservation, poverty reduction, and livelihood improvement is a necessity.
6. Soil degradation and loss of productive land are serious environmental problems in Nepal. With the increasing population and growing need for food, agriculture is being expanded to sloping lands and forests. The heavy monsoon rains and fragile mountain slopes are vulnerable to loss and degradation of land and soil through landslides, erosion and river cutting. It is estimated that as much as 5% of all landslides in Nepal are associated with newly constructed roads and trails.
7. Solid waste is a common environmental problem in urban areas. The major cities have experienced high rates of population growth and unmanaged urban development, which have resulted in an increasing volume of solid waste. The main sources of solid waste are households in urban areas. Slightly over 14% of the population lives in the 58 municipalities; they generate more than 80% of all solid waste. About two thirds of the waste materials are organic.
8. The impacts of inappropriate solid waste disposal, such as on rivers and human health, are substantial. The disposal of waste into local rivers has adversely affected the quality of water and the esthetic value of rivers and cities. This problem is particularly acute in Kathmandu Valley.
9. The municipalities are responsible for solid waste management. However, most municipalities do not have adequate resources and technical expertise to manage solid waste disposal. Solid waste disposal in landfill sites has become socially very sensitive and people's participation in it is generally weak. Lack of suitable infrastructure, such as landfill sites, is also a problem in urban areas.
10. Nepal is rich in water resources. Over 6,000 rivers and streams drain the country. With a rapid increase in population, demands for drinking water, sanitation, irrigation, industry, energy, and recreation have also increased. Water shortages and water pollution are serious problems in urban areas because of rural-urban migration, population growth, and unplanned urbanization. The problem of securing a safe drinking water supply is very serious, particularly in Kathmandu Valley.
11. There is evidence that water quality is deteriorating rapidly in urban areas. Urban areas generally lack infrastructure for collection, treatment, and disposal of sewage. Limited facilities built for this purpose are also either ineffective or nonfunctional. Drainage is a common problem, particularly in the Terai. As few houses are connected to the wastewater system, untreated domestic waste is discharged into rivers. Most households in rural areas do not have latrines; they defecate in open areas such as riverbanks and public lands. Likewise, most of the industrial effluents are directly discharged into rivers. All of these practices contribute to surface and groundwater pollution.
12. Water pollution has become a serious public health problem. Biological
water pollution, combined with inappropriate sanitation and hygiene
practices, are responsible for water-related diseases such as diarrhea,
typhoid, skin diseases, and intestinal worms.
13. Water pollution has also adversely affected aquatic ecosystems. Nepal's rivers have rich aquatic biodiversity, which is threatened due to growing water pollution. The rivers of Kathmandu Valley, particularly in the core city areas, have already lost aquatic biodiversity.
14. Air pollution is a serious concern in urban areas due to the dust generated by vehicles, increasing use of fossil fuels for transportation, and concentration of industries. Air pollution by industrial emission is a local concern in many areas. Kathmandu Valley is especially vulnerable to air pollution due to its topography (the bowl-shaped valley), rapid and haphazard urbanization, and significant increase of vehicular transport in narrow streets. In addition, the poor maintenance of the roads aggravates air pollution by contributing particulate matter to the air.
15. The transport sector is the largest contributor to total emissions of pollutants in Kathmandu Valley followed by the household, industrial, and commercial sectors. Gasoline is the largest contributor to the total combined emission of all pollutants, while fuel wood and coal are also major contributors. With the improved technology of brick kilns, pollution from this sector is expected to be reduced in Kathmandu. Indoor air pollution is also causing serious health hazards due to the burning of fuel wood in unventilated rural households.