According to WHO air pollution is defined as contamination of the indoor and outdoor atmosphere by various physical, biological, and chemical materials. The migration of People from all regions towards the capital city(Kathmandu) resulted in an increment of the population at a high rate. 90 percent of the world population lives in a place where air quality is unable to meet WHO air quality guidelines Nowadays uncontrolled urbanization and haphazard infrastructure development lead to an increment in air pollution. Kathmandu become one of the most polluted cities in the world. The emission of combustion gases from the vehicle is responsible to produce greenhouse gases

Due to the lack of public transportation system, the use of private vehicles is increased. The emission of harmful gases from vehicles contaminates air to a great extent. Unmanaged dumping sites, use of old vehicles, brick kilns, the industry also produces air pollution. According to WHO, the Death of about 7 million people is caused due to air pollution in the world. . A high concentration of CO forms carboxyhemoglobin which causes heart attack and affects the nervous system. Similarly, NO2 and SO2 cause bronchitis and eye irritation, cancer respectively Patients with lung cancer, respiratory illness, eye infection, asthma, various heart diseases are increasing day by day in the context of Nepal. There is a lack of adequate research on air pollution, the issue of air quality, and its consequences. An awareness program should be implemented to aware people of the effect of air pollution and safety precaution measures. The government should be responsible for enacting laws and regulations to safeguard citizens from air pollution. People should have access to public transportation, which will minimize the need for private cars and vehicles. Alternative routes for cycling should be developed.

https://www.who.int/news/item/25-03-2014-7-million-premature-deaths-annually-linked-to-air-pollution