A new report from UNICEF says two billion children around the world breathe toxic air on a daily basis.  Of that number, 300 million kids are exposed to pollution levels more than six times higher that standards set by the World Health Organization.

The UNICEF reports says that level of pollution can cause serious physical damage to these children, including harming their developing brains.  Much of this pollution is caused by "factors such as vehicle emissions, heavy use of fossil fuels, dust, and burning of waste".  It's a leading factor in child mortality.

"Air pollution is a major contributing factor in the deaths of around 600,000 children under five every year, and it threatens the lives and futures of millions more every day," said Anthony Lake, executive director of UNICEF.  "Pollutants don't only harm children's developing lungs.  They can actually cross the blood-brain barrier and permanently damage their developing brains and, thus, their futures.  No society can afford to ignore air pollution," Lake added.

South Asia has the largest number of children living in such areas at about 620 million, followed by Africa with 520 million and the East Asia and Pacific region with 450 million.

The UN agency, which promotes the rights and well-being of children, published the study in advance of the COP22 climate-change talks scheduled to take place in Morocco from 7 November to 18 November.  UNICEF will push world leaders for more robust measures to reduce pollution, increase children's access to healthcare and to monitor and minimize children's exposure to polluted air in their countries.