# Air Pollution in Kathmandu: What Travellers Should Know

_Published 10 July 2026_

Kathmandu sits in a bowl-shaped valley where dust, traffic fumes and smoke can become trapped. Air quality varies a lot by season, so it's worth knowing when it's worst.

**Quick answer:** air pollution is usually **worst in winter and spring**. Cold air traps pollution in the valley in winter, and from **March to May**, smoke from forest fires and crop burning adds to it, sometimes pushing the AQI to very unhealthy or hazardous levels. Air is usually **cleanest during the monsoon** and just after.

## Why the air gets bad

- Vehicle exhaust and road dust
- Brick kilns and industry around the valley
- Forest fires and agricultural burning, especially in spring
- The valley's shape and cold winter air, which trap pollution

## Protecting yourself

- Check the AQI on a reliable app each day.
- Wear a well-fitting N95/KN95 mask on bad days, especially in traffic.
- Plan outdoor activities for early mornings or after rain.
- Spend smoggy days in the hills: Nagarkot, Dhulikhel or Pokhara often have cleaner air.
- If you have asthma or heart or lung conditions, take extra care and bring medication.

## Effect on trips

Haze can hide mountain views in spring. The clearest skies are usually October–November. See [Kathmandu weather by month](/blog/kathmandu-weather-by-month) and [best time to visit](/blog/best-time-to-visit-nepal).

## Frequently asked questions
### Is Kathmandu polluted?
Air quality is often poor in winter and spring.

### When is air quality worst?
Usually March–May, when forest fire smoke adds to pollution.

### Should I wear a mask?
Yes, an N95/KN95 on bad days.

### When is the air cleanest?
During and after the monsoon.


Web page: https://himalayanhiking.com/blog/air-pollution-in-kathmandu