Water and air pollution in Nepal

Water pollution is the contamination of water by sewage, chemicals, pathogens or sediment that makes it unsafe for use; air pollution is the presence of harmful gases and particles in the atmosphere. Both are among the most serious environmental and health problems in Nepal.

Severity of water pollution in Nepal

1. Urban rivers turned into sewers – the Bagmati, Bishnumati and Dhobi Khola in Kathmandu receive untreated sewage and solid waste; dissolved oxygen is near zero in the dry season.
2. Microbial contamination – many piped and tanker supplies contain faecal coliform; outbreaks of cholera, typhoid and diarrhoea occur every monsoon.
3. Arsenic in Terai groundwater above the national standard (50 µg/L) in districts such as Nawalparasi, Rautahat and Bara.
4. Iron, manganese, ammonia and nitrate in Kathmandu valley and Terai groundwater.
5. Industrial effluent – tanneries, distilleries, dyeing and paper mills in industrial corridors discharge directly into rivers.
6. Agro-chemicals and sediment in rivers and wells.

Severity of air pollution in Nepal

1. Kathmandu valley – PM2.5 often many times the WHO guideline in winter and spring due to vehicles, road dust, brick kilns and waste burning, made worse by the bowl-shaped valley and temperature inversion.
2. Terai cities (Birgunj, Biratnagar, Bhairahawa) – industrial emissions and cross-border haze from the Indo-Gangetic plain.
3. Indoor air pollution – about half of households still cook with firewood, harming mainly women and children.
4. Health burden – air pollution is among the leading risk factors for death in Nepal (respiratory and heart disease, lung cancer).
5. Other effects – flight delays, damage to heritage, black carbon speeding snow melt.

Plans to solve the problem effectively and in a short time

Short-term (1–2 years, quick wins)

• Strict vehicle emission testing; remove vehicles older than 20 years from the valley.
• Finish and pave dug-up roads; sprinkle water; cover construction sites and trucks.
• Ban and fine open burning of waste; daily waste collection.
• Air quality alerts and school closures on hazardous days; masks for vulnerable groups.
• Test drinking water sources; chlorinate supplies; household treatment (boiling, filters, chlorine) during the monsoon.
• Stop direct dumping of waste into rivers; enforce existing effluent standards with fines.

Medium-term (3–5 years)

• Electric public buses and incentives for electric vehicles and induction cooking, using Nepal's hydropower.
• Convert all brick kilns to cleaner zig-zag technology.
• Complete sewer interceptors and wastewater treatment plants along the Bagmati (Bagmati Action Plan).
• Arsenic-safe deep tube wells and community treatment plants in the Terai.
• Effluent treatment plants in industrial estates.

Long-term and supporting

• Land-use planning, green belts and satellite towns.
• Continuous monitoring networks for air and water with public data.
• Health education through schools and FCHVs.
• Clear roles for federal, provincial and local governments under the Environment Protection Act 2076.
• Regional cooperation on cross-border haze.

Quick results come from enforcing existing rules and fixing visible sources (dust, burning, old vehicles, untreated water); lasting results need investment in clean transport and sewage treatment.