A thick layer of smog blanketed Kathmandu valley for the second day today with the haze threatening the health of valley denizens.

Earlier, in January first week, Kathmandu had witnessed unprecedented level of air pollution.

Environmentalists and meteorologists cited several reasons for this build-up of toxic haze in the valley.

They believe this is the result of dozens of wildfires raging on around the valley for the last few weeks coupled with air pollutants emitted from vehicles, industries and burning of waste in urban areas. The situation has been further exacerbated due to stagnant air inside the valley and lack of humidity as the valley has not witnessed rainfall for a long time.

Indu Bikram Joshi, deputy director general of Department of Environment said such a condition had been anticipated, but not in such a large scale.

Air Quality Index (AQI), at several places in Kathmandu valley exceeded AQI 300. Areas with above AQI 300 were Bhaisepati, Kirtipur, Bhaktapur and Ratnapark. Bhaisepati this afternoon recorded AQI above 370. Yesterday, it was 440.

Environment Engineer Riya Shrestha said the bowl-shape topography of the valley had contributed greatly as air pollutants got trapped. According to her, "Apart from the topography, trans-boundary air pollution from various parts of neighbouring India, vehicular emission and wildfires had exacerbated the problem, especially, due to lack of rainfall."

Issuing a special bulletin today, the Department of Hydrology and Meteorology stated that the haze would continue for at least two more days as air in most parts of the country was static. The department said lack of air movement and moisture had trapped pollutants in the thick haze above Kathmandu city.

Meteorologist Manju Basi said, "We do not expect the westerly wind to enter the country and bring air movement for at least two more days. So we do not see the possibility of rainfall or sign of drastic decline in pollution level."

Meanwhile, the Ministry of Health and Population issued a public appeal urging all to refrain from going outdoors unless for emergencies.

It urged the elderly, children and ailing people to take special care of their health and stay indoors.

A version of this article appears in the print on March 28, 2021, of The Himalayan Times.