After witnessing two back-to-back hazy days, residents of Kathmandu Valley woke up to a sunny morning on Wednesday hoping that warm afternoons and clear skies would return.

The bright sunny day made them feel as if the polluted air from the day before had disappeared all of sudden. But their hopes were dashed as the air quality of the capital didn’t improve drastically. It was still “very unhealthy”.

On Monday and Tuesday, the air quality index in Kathmandu soared to hazardous levels, creating a buzz among the members of the public and making headlines across media platforms.

“The air quality seems to have improved on Wednesday afternoon. It has gotten slightly better than the last couple of days. However, it is still polluted and unhealthy,” Bhushan Tuladhar, an environmentalist who closely follows urban issues including pollution, told the Post.

Following the sudden decline in air quality in the Valley, government agencies, otherwise indifferent towards the issue, had swung into action by issuing notices advising people to stay safe and avoiding outdoor activities.

However, experts say what happened in the last two days was not unexpected. In reality, residents of Kathmandu Valley have been breathing unhealthy and unsafe air almost every day for the last few years. “Pollution levels soar during the winter. It happens every year and is not something new.”

On Monday and Tuesday, when the overall Air Quality Index (AQI) readings hit the roof and quickly went from “unhealthy” to “very unhealthy” and then to “hazardous”, the valley’s topography and prevailing meteorological conditions also exacerbated the situation.

“Pollutants remained trapped in the air as the atmosphere was stable, and we also witnessed thermal inversion,” Shanti Kandel, a senior meteorologist with the Meteorological Forecasting Division, said while explaining why pollution levels shot up on Monday and Tuesday.

“The pollutants could not move up and get dispersed,” said Kandel.

But things changed on Wednesday as sunshine helped in allowing the trapped pollutants to get dispersed in the atmosphere. “Although some pollutants are still trapped in the air because of the Valley’s topography, the weather came to its rescue,” Kandel added.

While the improved weather condition on Wednesday provided a much-needed but temporary respite to the capital city, studies have for long been calling on authorities to take urgent actions to address the issue.

IQAir, a Swiss air quality technology company that provides real-time worldwide air quality data, showed that Kathmandu became the most polluted city in the world on Monday and Tuesday. But the same company has been showing that the capital’s air is unsafe for several years.

The World Air Quality Report, 2018, produced by the same group, ranked Kathmandu as the seventh most polluted capital city in the world, based on its average yearly PM2.5 level.

The report, which also ranked Nepal the eighth-most polluted country, recorded the annual average PM2.5 level for Kathmandu in 2018 at 54.4 micrograms per cubic meter (μg/m3), an increase from 45.9 μg/m3 in 2017.

Its latest report World Air Quality Report, 2019, once again placed Kathmandu as the sixth most polluted capital in the world with an annual PM2.5 concentration of 48 μg/m3.

While the concentration level of PM2.5, the most harmful of all air pollutants, was not recorded as “hazardous” in those reports, it wasn’t found to be safe either.

The WHO recommends an annual mean exposure threshold of 10 μg/m3 to minimise the risk of health effects from PM2.5. However, the UN agency cautions that no exposure level is free of health impacts.

The US Air Quality Index (AQI), which converts pollutant concentrations into a colour-coded scale of 0-500 for representing the level of associated health risk, has set “good” range for PM2.5 (12μg/m3), slightly higher than the WHO Air Quality Guideline (10μg/m3).

Still, the PM2.5 concentration for Kathmandu has remained unsafe for the general public for at least three years, as the PM2.5 level has been continuously hitting the “unhealthy for sensitive groups” mark.

This means that the general public and sensitive individuals, in particular, are at risk of experiencing irritation and respiratory problems.

That the AQI reading for Kathmandu exceeded 600, means the air quality was more than ten times worse than the US AQI standard. Likewise, with an overall concentration of 667 μg/m3 of PM2.5 on Monday at 9:45 PM, the numbers exceeded the WHO Air Quality Guideline by 66 times.

“It came as a shock and as a warning call. This is also because we had been breathing clean air in the last ten months when there was not much movement due to the pandemic,” said Tuladhar. “Now, it is like we have come out of a cinema hall after watching a movie and our eyes can’t adjust to the brightness outside. The air is still polluted and unhealthy.”

Bhupendra Das, an environmental specialist with expertise in clean energy and air pollution, is also not surprised by the latest spike in air pollution.

“During winter, the air gets severely polluted. Things improve with the onset of the monsoon,” said Das. “But even during the summer, air pollution levels are around five times higher than the national threshold limit,” said Das, who is an air quality specialist at Nepal Energy and Environment Development Services. “While the current PM2.5 levels are more than 30 times more than the safety guidelines, it hovers around 300 from December to February.”

Emission from vehicles, industries, brick kilns, waste burning, road improvement, and construction sectors are the major sources of air pollution in the Kathmandu Valley. However, nothing much has been done in the last few years to address the problem.

“It is one of those days when the air is nice and clear in the afternoon before it worsens in the evening,” said Tuladhar describing Wednesday’s weather.

“We are not out of the woods yet. Nothing much has been done to improve the air quality as air pollution has never been a priority. But it is not just an environmental issue, it is a public health issue.”

While authorities have not come up with concrete and long-term actions, they have failed to control open waste burning, which has gone unabated in various parts of Kathmandu Valley.

“The volume of coal imported by industries and brick kilns has increased. Then there are open waste burning as well as agricultural residue burning, even in areas like Bhaisepati,” said Das. “Open burning is happening in major areas like Tribhuvan University and other core areas of the Valley. We have not been able to even check such waste burning.”

Das’s study on open burning of waste in the municipalities of Nepal revealed that burning waste releases a dangerous amount of pollutants into the atmosphere.

His research found out that of the 319 waste piles identified during the study, 137 or 43 percent were actively burning in different routes of the valley’s urban and suburban areas.

The report estimated that municipalities in the valley burn about 7,400 tonnes per year or 20 tonnes of solid waste every day, which is three percent of the total waste produced.

“Likewise, pollution from agricultural residue burning, which has picked up in Tarai, also travels to Kathmandu with the wind. The cumulative effect is seen in Kathmandu,” said Das. “Despite such a dangerous level of pollution, there is no research and development in this area, which is the result of a lack of concern from responsible authorities.”

With the recent air pollution of record level, experts called on the government to announce a public health emergency as envisioned in the Kathmandu Valley’s Air Pollution Management Action Plan, which says the agencies can declare a public health emergency in case of AQI level crossing 300.

The action plan also comes up with several measures like imposing odd-even rules, banning open burning of waste, and cleaning of streets, among others.

Government agencies such as the Department of Environment and Ministry of Health coming up with advisories for the general public are part of minuscule actions, said Tuladhar.

According to experts, the government should cut down emissions in the transport sector and strictly enforce the green sticker rule while effectively implementing the existing action plan.

“But things have been stalled,” said Tuladhar. “For example, the procurement of electric buses has been delayed.”

He added, “We have failed to learn from our mistakes in the past despite knowing what needs to be done for improving air quality.”