Published by: The Kathmandu Post | 1 April 2025
Kathmandu Valley ranked the world’s most polluted city on Monday afternoon, with PM2.5 levels reaching 365 micrograms per cubic metre (μg/m3).
Amid widespread wildfires across Nepal, Kathmandu Valley became the most polluted city in the world on March 31, 2025. PM2.5 levels in Boharatar reached 365 micrograms per cubic metre, well into the hazardous range. Bhaisepati in Lalitpur recorded 333 micrograms per cubic metre.
Doctors warned that the spike in air pollution would worsen the spread of viral influenza, pneumonia, cough, and viral fever. Experts note that open fires and wildfires release particulate matter, nitrogen oxides, carbon monoxide, sulphur dioxide, lead, and mercury.
Authorities were criticised for failing to prepare for the season. An air quality expert warned that the lack of rainfall would lead to more fire incidents and that responsible agencies were not ready. Arson incidents in the Valley also contributed to worsening conditions.
Polluted air has been cutting the lives of Nepali people short by around five years, according to a report by the Air Quality Life Index. Experts say the authorities have not taken the issue seriously, and the worsening air quality has hit both public health and the economy.