Kathmandu Valley is is famous for its rich cultural and architectural heritage. However, over the past two decades, the valley has experienced a significant increase in pollution levels. One of the most visible forms of pollution in Kathmandu Valley is the high level of dust and smoke in the air. The city's rapid urbanization and population growth have also contributed to air pollution.

People from all over the country move to capital city kathmandu to persuit of better life and opportunities. This unique topographic structure creates a bowl-shaped basin that restricts the movement of air in and out of the valley.The restricted air movement means that pollutants generated within the valley tend to accumulate and get trapped, leading to high levels of air pollution. This makes the valley particularly vulnerable to air pollution, which has become a serious health hazard for its residents.

According to the World Health Organization (WHO), air pollution refers to the presence of any harmful substances in the air that can cause health problems, damage the environment, or interfere with the natural composition of the atmosphere. Air pollution is caused by both human activities and natural phenomena. Common sources of air pollution consist of  household combustion devices, motor vehicles, industrial facilities, and forest fires. Air pollution is a complex mixture of various pollutants, including particulate matter and gaseous pollutants like ozone, nitrogen dioxide, volatile organic compounds, carbon monoxide, and sulfur dioxide.

In the case of Kathmandu Valley, the rapid increase in vehicle numbers over the last 15 years has contributed significantly to air pollution. Private vehicles have been increasing at a faster rate than public transport vehicles that led  to a higher concentration of vehicles on the road, particularly during peak hours. Vehicles powered by diesel fuel causes harmful emission than powered by petrol. Kathmandu is also ranked as one of the most polluted cities in Asia, according to several reports. The high levels of air pollution in Kathmandu Valley have serious health impacts respiratory problems such as asthma cardiovascular disease, cancer, and other health problems.

Several policies and regulations are formulated to control air pollution since the 1990s. However, the implementation of these policies and regulations has not been effective enough. One of the challenges in addressing air pollution is the limited availability of air quality monitoring stations which hinder efforts to develop effective strategies. The lack of sufficient studies on air quality in urban and suburban regions is a major obstacle for developing effective strategies to address air pollution. The lack of awareness about adverse impact of poor air quality  have serious consequences for public health. Overall addressing air pollution in Kathmandu will require a sustained and coordinated effort from the government, private sector, civil society, and the public. This will require strong political leadership and commitment, as well as ongoing investment in monitoring, research, and the development and implementation of effective policies and initiatives. If immediate preventive measures are not taken in time, the air pollution situation in Kathmandu is likely to worsen, with serious consequences for public health and the environment.