As winter sets in, Kathmandu is as usual doomed to breathe in toxic airThe bowl-shaped structure of the valleys, which are surrounded by high hills, traps the heavily polluted air brought by winds from north India.
“Albeit Delhi might seem afar, air pollution in north India severely impacts the air quality in Nepal. Most importantly, the valleys in Nepal are more vulnerable if polluted air makes it into their environment,” said Shilshila Acharya, director at Avni Ventures, a waste management company.
Lahore became the world’s most polluted city in the world on Thursday, and schools and offices in Delhi remain shut due to air pollution.
Starting Thursday, the air quality levels began worsening in Kathmandu Valley as well, with an AQI reading of 152. On Friday, the AQI reading was 170 at 12:14 pm, which is ‘unhealthy’, and on Saturday, the reading was 171 at 8:45 am.
Likewise, various other cities across Nepal are experiencing ‘unhealthy’ air quality levels. AQI levels were recorded on Saturday at 10 pm in Biratnagar at 171, Birgunj at 183, Pokhara at 166, and Janakpur at 157.
“We have already started observing unhealthy air pollution levels in Biratnagar, Birgunj, and other areas that border India,” said Indira Kadel, senior meteorologist at the Climate Division, the Department of Hydrology and Meteorology.
Climate experts identify the breaking of inversion in the Indo-Gangetic plains, burning of agricultural residue, firewood, and plastic waste in India, and vehicular and factory emissions in Nepal as the major causes of smog in the country.
These pollutants that are suspended in the air, through inversion, form a layer closer to the ground, thereby directly affecting the quality of air.
“During winters, inversion takes place. The particles in the air, being heavier, form a blanket layer over the atmosphere and remain at the lowest levels in the air, and that’s the air we breathe,” said Kadel.
Inversion is a natural winter phenomenon that takes place both at local level and regional level. Regionally, the inversion formed in the Indo-Gangetic plains due to the burning of agricultural residue in Delhi and Lahore has broken and made its way into the atmosphere of Nepal.
“The inversion formed in the Indo-Gangetic plains–that includes Punjab, Delhi, Lahore – broke a few days ago. The hazardous levels of air pollution in the area made their way into the upper atmospheric layer, thereby making their way into Nepal,” explained Siva Praveen Puppala, Senior Aerosol Scientist at ICIMOD (International Centre for Integrated Mountain Development).
“This regional inversion adds about 20-30% of pollution to the existing pollution in the valleys during winter inversion,” said Puppala.
Given Nepal’s diverse geographical structures, valleys in Nepal experience the worst and lasting impacts of air pollution. The bowl-shaped structure of the valleys, which are surrounded by tall hills, prevents the heavily polluted air from escaping.
“If the polluted air makes it into Nepal’s valleys, it’ll be extremely difficult to get rid of the polluted air,” according to Prativa Manandhar, a senior meteorologist at Meteorological Forecasting Division. “The valleys–like Pokhara, Kathmandu and Dang–are like bowls, where the polluted air remains in the atmosphere until there’s rainfall or heavy winds to blow it away.”
As per IQ Air, the Swiss Group that manages real-time worldwide air quality data, Kathmandu’s AQI level is predicted to remain ‘unhealthy’ between 151-200, and ‘unhealthy for sensitive groups’ (101-150 AQI) for the next week with AQI readings ranging from 138-170.
Air pollution in dry seasons—November to June—is worsening every year. Studies conducted from 2000 to 2015 during dry seasons find a 50-60% increase in air pollution in the Kathmandu Valley.
“Air circulation is minimal during winters since there’s no rain or wind. As opposed to the monsoon or summer, where there is air circulation, the pollution that is produced within the valleys can’t leave the atmosphere in winter. In addition, the pollution brought by winds from north India, further exacerbates the existing air quality,” explained Manandhar.
Lower visibility, due to deteriorating air quality has thus become a recurring event every winter in Nepal.
The 24-hour advisory issued by the Meteorological Forecasting Division (MFD) on Friday states that the smog will cause low visibility that might impact road and air travel.
“The mixture of vehicular emissions, burning of firewood and plastics, factories, brick kilns, waste burning, road improvement, and construction sectors – forms smog, affecting the visibility and causing a lot of respiratory issues,” said Manandhar.
A study conducted by ICIMOD in 2017 found that about 35% of diesel-powered vehicles in Kathmandu Valley emit a visible plume of black smoke, contributing substantially to the ambient pollution.
PM2.5 levels of the transport sector are often recorded five times more than the World Health Organization (WHO) standards.
AQI levels measure five air pollutants—ground-level ozone, particle pollution (also known as particulate matter, including PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide.
The AQI level was recorded at 12:30 pm on Friday with PM2.5 at 92.5 micrograms per cubic metre (μg/m3) in Kathmandu Valley.
PM2.5 (particulate matter) are tiny particles or droplets in the air that are two and one-half microns or less in width.
Particles in the PM2.5 size are considered hazardous as they can travel deeply into the respiratory tract, reaching the lungs. Exposure to such tiny particles can cause irritation in the eyes, nose, throat, and lungs and cause coughing, sneezing, runny nose, and shortness of breath.
PM2.5 concentration in Kathmandu air on Friday was 18.5 times above the WHO’s annual air quality guideline value.
Another study finds that about 7,400 tonnes of solid waste are burnt every year that emit dangerous amounts of air pollutants—55 tonnes of PM2.5; 60 tonnes of PM10; 11,900 tonnes of carbon dioxide (CO2); 5 tonnes of sulfur dioxide; and 630 tonnes of carbon monoxide, among others.
The burning of agricultural residue and solid waste, which includes plastics at homes, to manage waste worsens the air quality.
“In the absence of a proper and timely waste management system and a lack of waste segregation at homes, people burn plastics and wastes from home as the solution. Burning plastics emit cancerous particles that are much more harmful than vehicular emissions. People believe that by burning waste, they’ve managed it locally but they fail to realize the consequences of their actions – not just to themselves but to the society at large,” says Acharya.
Speaking with the Post, experts identify various short-term solutions–from implementing existing policy solutions to conducting massive and rapid awareness campaigns–to deal with the smog.
“The immediate solution is to create massive awareness against the burning of agricultural residue, firewood, and plastic waste, especially now,” says Acharya, sustainability expert. “There are also policies against open burning in Nepal and policies that ban single-use plastics. It’s high time that we ensure these existing policies are implemented if we want breathable air.”
Given last years’ hazardous levels of air pollution in Kathmandu, experts are apprehensive the tale might repeat.
“Our last years’ outlook predicted droughts in the winter, which came true. We will publish this years’ predictions in a few weeks, which will give us a better idea of what the upcoming winter will look like,” says Kadel.
South Asia Climate Outlook Forum (SASCOF), which takes place annually, prepares seasonal climate information on a regional scale that provides a consistent basis for preparing national-level outlooks.
Nepal’s national outlook on climate is set to be published by the last week of November, which can guide Nepal’s climate policy for the upcoming months.
“While we can’t control the migrated winds, we can issue alerts about hazardous air quality levels to the public, based on our forecasts. In addition, the public should be supported institutionally – encouraging work from home, limiting outdoor activities–to prepare themselves for these changing weather conditions,” says Kadel.