The World Health Organisation (WHO) revealed Thursday that low and middle-income countries are bearing the brunt of air pollution, which causes as many as three million premature deaths worldwide every year.
Figures released by WHO's air pollution database show that 98 percent of cities with over 100,000 inhabitants in low and middle-income countries do not meet established air quality guidelines.
The number drops to 56 percent when measuring the qualitative situation in high-income countries.
This is concerning given that a drop in urban air quality increases the risk of stroke, heart disease, lung cancer, and chronic and acute respiratory diseases, including asthma, for people inhaling pollutants such as sulphate, nitrates and black carbon on a daily basis.
This is particularly dangerous since small and fine particulate matter penetrate deep into the lungs as well as the cardiovascular system.
Trends also show that while awareness is rising, the situation is showing few signs of improvement.
Figures derived from the study comparing 795 cities in 67 countries show that global urban air pollution increased 8.0 percent between 2008 and 2013, with the highest levels experienced in low and middle-income countries in WHO's Eastern Mediterranean and South-East Asia regions.
Annual mean levels in those regions often exceeded WHO limits by five to 10 times, followed by low-income cities in the Western Pacific region.
The report also found that the levels of urban air pollution has increased by more than 5 percent in over two-thirds of the cities in the Eastern Mediterranean, South-East Asia regions and low-income countries in the Western Pacific region.
In light of this, director of WHO's department of public health and environment, Maria Neira, warned that the situation was highly troubling.
"Urban air pollution continues to rise at an alarming rate, wreaking havoc on human health," she said.
"At the same time, awareness is rising and more cities are monitoring their air quality. When air quality improves, global respiratory and cardiovascular-related illnesses decrease," she added.
This year's World Health Assembly, held from May 24 to 30, will enable its 194 member states to discuss strategies seeking to enhance the global community's response to this global scourge.
