Kathmandu air pollution: causes, effects, mitigation

Air pollution in Kathmandu valley is a severe problem; PM2.5 levels in the dry season are often many times above the WHO guideline, and the city has at times been ranked among the most polluted in the world.

Causes of air pollution in Kathmandu valley

1. Vehicular emission – rapid increase in vehicles (especially motorcycles), old diesel buses and trucks, poor maintenance, adulterated fuel and traffic congestion.
2. Road and construction dust – dug-up roads for pipes and road widening, unpaved roads, construction of buildings, uncovered transport of sand and soil.
3. Brick kilns – burning coal and biomass, mostly in Bhaktapur and Lalitpur from December to May.
4. Industries – small industries and diesel generators.
5. Open burning of solid waste including plastic.
6. Household fuel burning – firewood, kerosene.
7. Forest fires in spring and trans-boundary haze from northern India.
8. Topography and weather – bowl-shaped valley surrounded by hills, temperature inversion in winter, low wind speed and no rain in the dry season trap pollutants.
9. Unplanned urbanisation – loss of greenery and open space.

Effects

Health

• Respiratory diseases: asthma, bronchitis, COPD, pneumonia.
• Heart disease, stroke and lung cancer.
• Eye and throat irritation, headache; children, elderly and traffic police most affected.
• Reduced life expectancy.

Environment and economy

• Smog and poor visibility; flight delays at Tribhuvan International Airport.
• Blackening and corrosion of temples and heritage monuments.
• Black carbon contributes to warming and Himalayan snow melt.
• Loss of tourism and higher medical costs.

Possible mitigation measures

1. Transport – electric vehicles and electric public buses; better public transport; emission testing and removal of old vehicles; quality fuel; walking and cycling lanes; traffic management.
2. Dust control – timely completion of road works, paving, water sprinkling, covering construction sites and trucks.
3. Industry – cleaner brick kiln technology (induced-draught zig-zag kilns), relocation of polluting industries, filters and stack standards.
4. Waste – ban and penalise open burning; segregation, composting and recycling.
5. Energy – electric cooking, solar, biogas instead of firewood and kerosene.
6. Greenery – tree plantation, parks, green belts.
7. Monitoring and enforcement – air quality stations, public AQI alerts, enforcement of National Ambient Air Quality Standards and the Environment Protection Act.
8. Awareness – masks on bad days, public participation, school programmes.
9. Regional cooperation to reduce cross-border pollution.