(CNN)Around 93% of the world's children under 15 years of age breathe air that is so polluted it puts their health and development at serious risk, accounting for 1.8 billion children, according to a report published by the World Health Organization ahead of its first global conference on air pollution and health in Geneva.
In 2016, 600,000 children were estimated to have died from acute lower respiratory infections caused by polluted air.
Air pollution is one of the leading threats to health in children under 5, accounting for almost one in 10 deaths among this age group, the report reveals.
"This is inexcusable. Every child should be able to breathe clean air so they can grow and fulfil their full potential" said WHO Director-General Dr. Tedros Adhanom Ghebreyesus in a statement.
Air pollution also effects neurological development and cognitive ability and can trigger asthma and childhood cancer, the report says. Children exposed to excessive pollution may also be at greater risk of chronic conditions such as cardiovascular disease in adulthood.
"Air pollution is stunting our children's brains, affecting their health in more ways than we suspected. But there are many straightforward ways to reduce emissions of dangerous pollutants," said Dr. Maria Neira, director of the Department of Public Health, Environmental and Social Determinants of Health at the WHO.
According to the WHO, children are more susceptible to pollution because they breathe more often, taking in more pollutants, and are closer to the ground, which is where some pollutants have higher concentrations.