More than three-quarters of these young children - 12 million - live in South Asia.
"Protecting children from air pollution not only benefits children".
One does have to wonder - when you take a step back and look around - how much of modern "stupidity" isn't the result of "ignorance" (as many people claim), but rather actual brain damage as caused by chemicals and particulate pollution (whether dementia, Alzheimer's, developmental disorders, etc).
Satellite imagery used to assess pollution levels around the world found that South Asian countries accounted for 12.2 million of the total number of affected children but that there is also a growing problem in African cities.
It called for a greater use of masks, air filtration systems and for children to avoid travelling when pollution levels are at their highest.
"The brains of babies and young children are constructed by a complex interplay of rapid neural connections that begin before birth", said Pia Rebello Britto, the UNICEF chief of early childhood development.
"No child should have to breathe dangerously polluted air - and no society can afford to ignore air pollution", Lake concluded. "It also benefits their societies - realized in reduced health care costs, increased productivity and a safer, cleaner environment for everyone", he stressed.
The paper outlines urgent steps to reduce the impact of air pollution on babies' growing brains, including immediate actions for parents to decrease children's exposure at home to harmful fumes produced by tobacco products, cook stoves and heating fires.
This is made worse by a higher breathing rate in children, which causes them to inhale more toxic air, according to the report.
· Reduce air pollution by investing in cleaner, renewable sources of energy to replace fossil fuel combustion; provide affordable access to public transport; increase green spaces in urban areas; and provide better waste management options to prevent open burning of harmful chemicals. This includes the prevention and treatment of pneumonia, as well as the promotion of exclusive breastfeeding and good nutrition.
The findings come at the time when India is facing the serious issue of air pollution. In November, with the onset of winter, pollution has been affecting people to a worrying level, with doctors recommending that residents in New Delhi, especially older people, and those with heart and respiratory ailments, should restrict time outside as well as physical activity.