A staggering two billion children in the world are breathing unhealthy air, risking serious health effects including damage to their lungs, brains and other organs, Unicef has said.
A new report by the organisation said 300 million children are exposed to pollution levels more than six times higher than standards set by the World Health Organisation, including 220 million in South Asia.
Of the two billion children at risk worldwide, the report puts 620 million of them in South Asia - mostly northern India. These alarming numbers hardly come as a surprise - New Delhi's air pollution, among the world's worst, spikes every winter because of the season's weak winds and countless rubbish fires lit to help people stay warm.
Another 520 million children are breathing toxic air in Africa, and 450 million in East Asia, mainly China, according to the report.
It combined satellite images of pollution and ground data with demographic patterns to discover which populations fell into the highest risk areas.
Children face much higher health risks from air pollution than adults: they breathe twice as quickly, taking in more air in relation to their body weight, while their brains and immune systems are still developing and vulnerable.
Unicef executive director Anthony Lake said the impact is shocking, with 600,000 children younger than five across the world dying every year from air pollution-related diseases.