A new World Health Organisation report has revealed that 93% of children in the world under the age of 15 years are exposed to highly polluted air that makes them vulnerable to major health problems. About 630 million of these 1.8 billion children are under the age of five.

The report was released ahead of the first WHO Global Conference on Air Pollution and Health that will begin in Geneva on Tuesday. It said the impact on children is worse in low and middle-income countries, where 98% of all children under five are exposed to PM 2.5 pollutants – particles with a diameter of less than 2.5 micrometres – above permissible limits set by the WHO, compared to 52% in high-income countries.

In low and middle-income countries in Asia such as India, 99% of children under five are exposed to PM 2.5 pollutants higher than WHO standards. In 2016, about 6 lakh deaths of children under 15 years were caused by the combined exposure to ambient and household air pollution, the report claimed. Cooking fuels such as wood, coal or dung cause household air pollution. The sources of ambient air pollution include vehicular emissions and garbage burning.

Air pollution accounts for one in 10 deaths of children under the age of five, the report said. Household air pollution and ambient air pollution led to more than 50% of acute lower respiratory infections in children under the age of five in low and middle-income countries, the world body said.

In 2016, household air pollution caused by solid fuel and kerosene resulted in about 38 lakh premature deaths, or 6.7% of global mortality. It is higher than the deaths caused by malaria, tuberculosis and HIV/AIDS combined, the report said. Of these deaths, 4.03 lakhs were children under the age of five.

“This [situation] is inexcusable,” said WHO Director-General Dr Tedros Adhanom Ghebreyesus. “Every child should be able to breathe clean air so they can grow and fulfil their full potential.”

The organisation urged nations, local administrations, inter-governmental organisations and scientists to take necessary measures to keep air pollution in check. The report suggested informing, educating and providing resources to health professionals, complying with the World Health Organisation’s global air quality guidelines by reducing the over-dependence on fossil fuels and investing in energy efficiency upgrades. The report also suggested increased use of renewable energy sources and minimising children’s exposure to polluted air by relocating schools and playgrounds away from sources of pollution.