Babies in South Asia were worst affected, with more than 12 million living in areas with pollution six times higher than safe levels. A further four million were at risk in East Asia and the Pacific. Unicef said breathing particulate air pollution could damage brain tissue and undermine cognitive development. Its report said there was a link to "verbal and non-verbal IQ and memory, reduced test scores, grade point averages among schoolchildren, as well as other neurological behavioral problems". The effects lasted a lifetime, it said.