Worst air quality situation of the Kathmandu Valley

The air pollution in the Kathmandu Valley has eased to some extent as a result of the rain that accompanied the windstorm on Saturday morning, and the weather in the valley has cleared up. This is what the valley looks like after the rain.

Due to the lack of rain, the pollution increased to a point where it was painful to the eyes. This had an adverse effect on the health of the common people. Kathmandu was at the forefront of the most polluted cities in the world.

The Kathmandu Valley continued to top the global list of cities with the worst air quality, according to the Air Quality Index (AQI) measurement taken at 6:15 am on Wednesday 9th April.

As per the latest data, Kathmandu recorded an AQI of 184, placing it in the “unhealthy” category. Following closely behind are India’s capital, Delhi, with an AQI of 180, and Kampala, Uganda, with 157.

Medical professionals have warned that Kathmandu’s air quality has reached levels that pose serious health risks.

Experts attribute the high pollution levels to prolonged dry conditions, which have allowed dust to accumulate in the atmosphere, as well as smoke from wildfires in surrounding forests.

Although pollution levels have slightly decreased over the past few days, Kathmandu remains the most polluted city in the world. Just a few days ago, the Valley recorded an alarming AQI of 352.

The Ministry of Health has issued an advisory urging citizens to take precautions, noting that Nepal’s air ranks among the most hazardous globally.

Doctors have advised the public to avoid outdoor activities, especially during the morning and evening hours.

According to the World Health Organization (WHO), an AQI below 35 is considered safe for human health, while values between 35 and 50 are still acceptable. However, any reading above 50 begins to pose health risks. Here’s how AQI levels are categorized:

51–100: Moderate – caution advised, 101–150: Unhealthy for sensitive groups (e.g., those with respiratory or heart conditions), 151–200: Unhealthy, 201–300: Very unhealthy, 301–400: Hazardous, 401–450: Extremely hazardous

The Air Quality Management Action Plan for Kathmandu Valley (2076 BS) classifies AQI levels above 300 as a public health disaster.

Moreover, Nepal has been witnessing reduced winter rains for four years, while lack of adequate rains despite pre-monsoon, increasing forest fires and dearth of environment-friendly infrastructures were aggravating air pollution.     

Air pollution in Kathmandu Valley stems from a combination of factors, including vehicular emissions, industrial activities (especially brick kilns), construction dust, burning of solid waste, and biomass for cooking and heating. Vehicular emissions, industrial activities, construction activities, solid waste burning, biomass burning, lack of adequate rainfall, open burning of refuse and waste, mountain-valley setting, lack of effective policies and implementation

The rapid increase in motorized vehicles, coupled with poorly maintained vehicles and traffic congestion, contributes significantly to air pollution, especially with tailpipe emissions and road dust. 

Brick kilns and factories, particularly those using coal, release pollutants like dust, smoke, and carbon monoxide, exacerbating air quality issues. 

Construction dust, often generated on or near streets, is a major source of particulate matter pollution. 

Open burning of garbage and waste, including wood, plastics, and other materials, releases harmful pollutants into the air. 

The use of wood, agricultural residue, and animal dung for cooking and heating in households contributes significantly to air pollution, especially during winter months. 

Environmentalists say lack of adequate rainfall has boosted air pollution this time in Kathmandu valley. 

Due to a lack of proper garbage collection and disposal infrastructure, large amounts of the population take to lighting their refuse on fire in order to get rid of it. 

The mountain-valley setting produces a thermal circulation that has been found to influence air pollution transport, especially in winter. 

Inactive civil society, lack of research, advocacy and lobbying, lack of mobilisation of human resources, lack of response from the government, unclear guidelines and policies, as well as their implementation, have all contributed to the problem. 

Air pollution can be controlled by making proper changes in raw materials, operation and system control. Dispersion of sources of air pollutants is the another method of controlling air pollution in industrial process. Contaminants should be distributed over a large area in less time and hence dilute the concentration of pollutants nears the source. Investigating the main source of inputs, contaminants should be collected which is the easiest solution of air pollution problem.

Expert opine that some specific measures will be appropriate to control air pollution. Unleaded petrol to reduce lead concentration in ambient air, the vehicles should be driven with electricity or hydrogen, methane as a source of energy, two stage combustion should be used to reduce the emission of NO2, evaporation should be controlled from fuel tank and carburetor. Use of filter, improvement in traffic management, dust particulate emitting industries started with electrostatic precipitator, introduction of electric powered trolley bus service and strictly implementation of emission control law may be effective in controlling air pollution.

Form another point of view, air pollution has been a nationwide problem as the Kathmandu Valley has its own air pollution generating behaviour, but air with pollutants it receives from outside are also larger contribution to make the air quality worst. Researchers claim that places outside the Kathmandu Valley also get polluted badly. Moreover, other than locally generated the pollutants, the matters generated over New Delhi, Hariyana, Punjab of India also arrive over Nepal’s western Terai and hills. So as pollutants even reach to lower reaches of the mountains as well. Therefore, an extra efficient technical instrument should be churned out with high level engagement.

Some professionals also had proposed deploying of Cloud Seeding to reduce the air pollution level in the Kathmandu Valley. This also raises questions like – is it available, is it affordable, can the topography tolerate its side effects, experiences where it was experimented and so many pros and cons. In Nepal’s context, this technology can be counterproductive, some experts explain.

However, it is easy to understand that Cloud seeding is a type of weather modification that aims to change the amount or type of precipitation, mitigate hail or disperse fog. The usual objective is to increase rain or snow, either for its own sake or to prevent precipitation from occurring in days afterward.

Cloud seeding is undertaken by dispersing substances into the air that serve as cloud condensation or ice nuclei. Common agents include silver iodide, potassium iodide, and dry ice, with hygroscopic materials like table salt gaining popularity due to their ability to attract moisture. Techniques vary from static seeding, which encourages ice particle formation in supercooled clouds to increase precipitation, to dynamic seeding, designed to enhance convective cloud development through the release of latent heat.

Methods of dispersion include aircraft and ground-based generators, with newer approaches involving drones delivering electric charges to stimulate rainfall, or infrared laser pulses aimed at inducing particle formation. Despite decades of research and application, cloud seeding’s effectiveness remains a subject of debate among scientists, with studies offering mixed results on its impact on precipitation enhancement. (By Purna N. Ranjitkar)