Ajay’s 63-year-old frame strains with each breath. He is lying on an emergency-room stretcher in one of Kathmandu’s large hospitals and he appears exhausted. Behind the oxygen mask, his eyes have the panicked, haunted look of a man who can’t breathe. He has chronic obstructive pulmonary disease, or COPD, an umbrella term for emphysema and chronic bronchitis. It is killing him.

COPD is most often associated with smokers, but Ajay, like many seeking help at Kathmandu emergency rooms, has never smoked. He has, however, worked at road construction in the capital for many years, labouring with a pickaxe and inhaling fumes daily from the eclectic mix of vehicles: ancient buses spewing black smoke, three-wheeled tempos in varying degrees of disrepair and tractors with open motors. Countless cars and legions of motorcycles add to the exhaust fumes, through which pedestrians, bicycles and animals weave in a chaotic flow of traffic that somehow remains in motion.

Nepal generally evokes images of a pristine mountain nation on top of the world. The thick cloud of pollution that threatens to suffocate Nepal’s largest city, however, provides a stark contrast to this reputation. While there are several environmental crises converging here – severe water shortages, for instance, have become status quo – none is as dire as air quality. In the past 10 years, the number of vehicles on Kathmandu’s streets has risen threefold. The problem has become so acute that many of its 1.74 million residents are left wondering: at what point will their city become unliveable?

Kathmandu has experienced a threefold increase in the number of vehicles on its streets since 2000. Photograph: Sara Germain Photograph: Sara Germain

Nepal’s air quality ranks 177th out of 178 countries, according to Yale’s 2014 Environmental Performance Index (EPI), better only than Bangladesh. As a physician working in one of Kathmandu’s main teaching hospitals, I see a disproportionate amount of patients with respiratory ailments who are admitted to the wards on a daily basis, the victims of dirty air. Walking to and from work along the crowded, exhaust-choked streets, I sometimes wonder how more people are not sick.

The view from my Kathmandu rooftop certainly seems to bear the EPI findings out. On many days, the relatively close Himalayan mountains are obscured by smog, the brick apartment buildings that form Kathmandu’s skyline shrouded in an oppressive cloud. Those new to Kathmandu frequently complain of sore throats and itchy eyes within a few days of arrival.

“I see rapid changes each time I return,” says Anobha Gurung, a Kathmandu-born doctoral candidate at Yale who is studying the air quality in her home city. “Now it is a common sight to see a gray haze for the valley, especially during the winter months, and city residents venturing out of homes wearing masks.”

Gurung and her colleagues have found that during surges in Kathmandu traffic congestion, the level of small particulate matter can measure over 500 micrograms per cubic metre, or 20 times the World Health Organisation’s safe upper limit. By comparison, the recent smog alarm that led Paris to ban cars peaked at just over a fifth of that level: 110 micrograms per cubic metre.

The sight of Kathmandu residents wearing masks is an increasingly common sight. Photograph: Sara Germain Photograph: Sara Germain

Further data is hard to come by. Nepal’s government has several monitoring stations throughout the city, but they have been abandoned for at least six years. Samir KC, a Nepali researcher based in Vienna who has studied pollution and monitoring in Kathmandu, says the monitors were allowed to fall into disrepair. “During our [study], we found that the repair was done and it was up to the government to pay the bill and start the monitoring,” he said. “Nothing happened.”

Most of the research on air quality in Nepal focuses on indoor pollution: cooking fires are ubiquitous in the countryside. In the capital, however, this may be misleading. “Cooking fires are definitely not the cause, as most households use [propane] gas,” says Samir KC. “Suspended particles including dust, exhaust from vehicles and diesel generators are the main culprits.” Of these, it is vehicle congestion that is most strongly correlated to worsening air quality, according to Gurung’s research.

Findings such as these pose a developmental conundrum for governments intent on modernising. It is one thing to stamp out indoor cooking fires as part of the path towards progress. It is quite another, especially in Asian cities that are increasingly oriented around cars, to try to reduce the emissions that come hand-in-hand with industrialisation and urbanisation.

The level of small particulate matter in the air in Kathmandu can reach 20 times the WHO’s safe upper limit. Photograph: Sara Germain Photograph: Sara Germain

What’s more, modernisation has also fuelled the appetite for electricity, yet infrastructure has not kept pace. Kathmandu endures daily, scheduled “brownouts”. This has had the predictable consequence of driving people to use generators: when the power goes off, their dull roar can be heard throughout the city, pumping yet more toxic fumes into the air.

At present, the Nepali government is either unwilling or unable to make changes. Urban planning of the kind that addresses ecological issues is largely absent. But the situation is not lost on ordinary Nepalis. Daily, newspapers print letters decrying the situation and demanding better from elected officials. Air quality is a frequent topic of conversation here; facemasks are so commonplace, they are now sold in trendy designer styles made of patterned cloth. Other people use scarves to shield their faces.

In the hospital, for the time being Ajay continues to gasp for air. For smokers with COPD, one of the only effective interventions that improves longevity is to quit smoking. But Ajay and those like him have no cigarettes to give up. The air they breathe is making them sick. For them, the question of whether the city will become unliveable is moot. It already is.

• Andrew Lodge is a doctor at a teaching hospital in Kathmandu

• How are cities' accelerating growth affecting their poorest children?

