Last week, a sanitary worker at the head office of the Agriculture Development Bank Limited was caught while burning waste at the nearby Maitighar Mandala, a traffic island. The man was caught by none other than the chief of the environment department at the Kathmandu Metropolitan City, Sarita Rai, who was on her way to the office. Rai said she stopped her vehicle and asked the staffer to douse the fire immediately.

Rai added she made the staffer aware about a notice issued recently by the metropolitan city office that prohibited open burning. “The staffer pledged that he would not repeat the mistake in the future and stop others from doing the same,” she said.

Kathmandu regularly makes headlines as one of the world's most polluted cities. Burning of waste out in the open is one of the chief reasons behind the Valley’s deteriorating air quality, environment experts say. Incidents of waste-burning are increasingly being reported in the Valley of late and its air quality index is deteriorating by the day. Rai, citing a recent incident, said that even educated people appear aloof about the gravity of the problem.

“A few days ago, we found employees at Thapathali Campus burning waste,” Rai said. “How can we expect change when even educated people don’t consider the consequences of their actions?”

On Wednesday, the PM2.5 level of Kathmandu’s air reached an alarming 160, according to a tracker by IQAir, the Swiss air quality technology company. The air quality level of Tulsipur, a city in the midwestern part of Nepal, reached a maximum of 187, the highest in the country.

IQAir collects real-time air-quality data from around the world. PM 2.5 refers to particulate matter or solid and liquid droplets in the air that are less than 2.5 micrometres, or 400th of a millimetre, in diameter.

When PM2.5 reaches 151 to 200 μg/m3, air quality is considered unhealthy, according to the United States Environment Protection Agency’s air quality index. In that situation, everyone may experience problems, with sensitive groups more at risk. When the AQI exceeds 300 μg/m3, it is considered “hazardous” for everyone.

The rise in open waste burning incidents across the Valley shows that the authorities have failed to keep a check on one of the leading contributors to air pollution, experts say.

The Kathmandu Metropolitan City prohibited open waste-burning in its jurisdiction, issuing a notice a few weeks ago. The metropolis also encouraged other local units to follow suit, but only Chandragiri Municipality has issued such a notice so far.

Kathmandu metropolis is neither the only local unit in the Valley affected by the worsening air pollution nor can it control it solely, said Bhupendra Das, an air quality expert from Clean Air Asia. “Other agencies concerned should also shoulder responsibilities to lessen the air pollution,” he said.

A study on waste burning has estimated that municipalities in the Valley burn about 7,400 tonnes of waste per year or 20 tonnes per day—which is three percent of the total waste produced.

The major sources of air pollution in the Valley also include emissions from vehicles, industries, brick kilns, road upgrade drives, and construction sectors; geographical factors, too, play a role.

Officials concede that there are no proper mechanisms in place to check the emissions.

Studies carried out in the past have found that nearly half of the vehicles plying the Capital’s streets are not complying with the national standard.

The Department of Transport Management carried out vehicle exhaust tests and provided green stickers to the vehicles but officials and experts doubt the department’s commitment to the drive.

“We have proposed to start vehicle exhaust testing but the plan is still in its infancy,” said Rai, the metropolis’s environment department chief.

“We have to take consent from provincial and federal government agencies and they are also responsible to lessen air pollution.”

Likewise, firing is set to start in many brick kilns of the Valley shortly.

Experts say that the government has not yet introduced measures to control pollution levels of factories and kilns.

Kathmandu is a bowl-shaped Valley, with many mountain ranges around. It is also surrounded on both sides by China and India, economic giants who in their own rights still have many pollution problems. Like Kathmandu, cities from both the countries regularly feature in the list of world’s most polluted cities.

Das, the air quality expert, said that to reduce pollution in the air, everyone concerned should commit themselves to the cause.

“Even awareness can play a vital role in reducing pollution levels,” he said. “Reducing pollution in the air is not easy. But it is not an impossible task either.”