Toxic air is impeding, and in some cases claiming, the lives of children worldwide.

According to a study from the World Health Organization (WHO), more than 90% of the world’s young people — or roughly 1.8 billion children — are breathing toxic air, reports the Guardian.

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“Polluted air is poisoning millions of children and ruining their lives,” said WHO Director-General Dr. Tedros Adhanom in a statement from the organization. “This is inexcusable — every child should be able to breathe clean air so they can grow and fulfil their potential.”

The findings were released at the launch of the first global conference on air pollution and health in Geneva, where nations and cities are expected to make new commitments to cut air pollution, according to the report.

In 2016, approximately 600,000 children alone died from acute lower respiratory infections caused by dirty air, noted CNN in its coverage.

Medical experts have identified the crisis in both rich and poor countries, with repercussions ranging from low birth weight to poor neurodevelopment, asthma to heart disease, the report said.

Children are more susceptible to these health issues, as pollutants are often more concentrated at ground level and kids’ developing organs and nervous systems are more vulnerable to long-term damage than adults.

Dr. Maria Neira, WHO director of public health and the environment, identified various, basic ways to reduce the toxic air and its potential health impacts, noting that there were “many straightforward ways to reduce emissions of dangerous pollutants,” including “accelerating the switch to clean cooking and heating fuels and technologies, [and] promoting the use of cleaner transport, energy-efficient housing, and urban planning.

“We are preparing the ground for low-emission power generation, cleaner, safer industrial technologies, and better municipal waste management,” she said.

In a statement, Mark Watts, executive director of the C40 Cities group which partners with cities around the world in tackling the climate crisis and air pollution, said: “The moral and practical case for urgent, bold, and far-reaching action to reduce emissions, including calling an end to the fossil fuel era, is now utterly irrefutable.”