Based on air pollution levels, Kathmandu has been ranked as the fourth most polluted city in the world. Currently, the air quality in Nepal’s capital is considered poor, with PM2.5 levels of 184 micrograms per cubic meter (μg/m3) at 9:45 a.m. PM2.5, the primary airborne pollutant less than 2.5 micrometers in diameter, poses a serious health risk, according to data from global air quality reporting organization IQ AirVisual.