ADB_book_18 April.qxp - Himalayan Document Centre - icimod

in worsening public health conditions, deterioratingquality of life, and increased economic costs tosociety. While this affects people of all income levels,the poor are most vulnerable. They have fewresources or alternatives to protect themselves fromsuch adverse impacts as seasonal drying out ofsurface water sources, pollution of groundwater, orspread of sanitation-related diseases.DrainageDrainage to cope with surface runoff is oftendeficient in Nepalese urban areas. This is mostevident during the rainy season; the limited lengthsof drains that exist in urban areas are often filled withwaste, including plastics and dirt. As a result, thesurface runoff either infiltrates the ground or flowsinto natural drains through streets and lanes, leavingthe towns muddy and dirty. Urban areas in the Terai(where the natural gradient is very flat) oftenexperience serious drainage problems: flooding andrise in groundwater tables are common. This rendersthe existing wastewater disposal system ineffective.These deficiencies obviously pose a serious threat tothe health and sanitation of the residents. Hillmunicipalities also suffer from lack of drainage,although to a lesser extent than the Terai towns.According to ADB (2000), more than 25% ofhouseholds of greater Kathmandu and 32% of thoseof Bhaktapur suffer frequent flooding.Air PollutionAir pollution is emerging as a serious concern in themajor urban areas of Nepal in general and inKathmandu Valley in particular (see Chapter 7). Thedeterioration in urban ambient air quality resultsfrom vehicular emissions, industrial emissions,burning solid waste including plastics, constructionwork, poor maintenance and narrow roads, andadulteration of fuel. In urban areas total suspendedparticles (TSP) and PM10 (particulate matter smallerthan 10 micrometers in diameter) are the majorconcerns. Other pollutants such as SO 2 and NO x arealso increasing although still below Nepal’s AmbientIndustrial Air Pollution, KathmanduNEFEJAir Quality Standards and WHO guideline levels. Inareas where traffic is high, TSP and PM10 generallyexceed national and WHO guideline values. Thisindicates that the major source of TSP and PM10 isroad traffic; the condition of vehicles and of the roadsurface are contributing factors in addition to thetype and quality of fuel. Industries probably follow asthe next major source of urban air pollution.Air quality monitoring in Kathmandu shows thatthe air is routinely not clean enough to breathe inplaces like Putalisadak, Patan, and Thamel. Pollutionalso regularly obstructs the visibility levels of thescenic landscape of the Himalayas. According to astudy, the number of foggy days in Kathmandu hasincreased from about 35–40/year in 1970 to more than60/year in 1993, the most recent year for which reliablestatistics are available (URBAIR 1996). KathmanduValley is particularly vulnerable to air pollution due topoor dispersion chances in its bowl-shapedtopography. In the smaller urban areas, indoor airpollution resulting from use of biomass fuel, firewood,cow dung cake, and crop residues is at present ofmore concern than outdoor air pollution.Adverse effects of air pollutants on humanhealth can be acute or chronic. Respiratory infectionis among the top five diseases in Nepal, occurringmainly due to prolonged exposure to smoke and dust(CBS 1998). Acute respiratory infections (ARI)continue to be one of the leading causes of deathamong young children, causing over 30% of deaths inchildren under five years of age (DOHS 2001). InKathmandu Valley, 3.6% of the respiratory diseasesamong children are estimated to be caused by TSP(IUCN 1999). Air-pollution-related ailments such aspneumonia, bronchitis, and asthma are nowbecoming very common in Kathmandu Valley (IUCN1999).Traffic CongestionThe number of motor vehicles in the larger urbancenters has increased rapidly in recent years. Thishas not been matched by provision of roads andinfrastructure, leading to persistent trafficcongestion, particularly in Kathmandu Valley towns.Urban development is taking place without adequateplanning or provision of transport infrastructure, andwith inadequate consideration of the nature andcomposition of the traffic. Urban roads arecommonly narrow and crooked, and the roadnetwork function is poor. There is no or insufficientparking space. The mixture of vehicle types, poordriving, bad parking, and roadside trading add totraffic congestion. The consequences of this arelonger travel times, greater levels of air and noisepollution, and less efficient fuel consumption (ADB2000; Adhikari 1998; UNEP 2001).112 Environment Assessment of Nepal : Emerging Issues and Challenges