The report comes at a time when north India, particularly Delhi and adjoining areas, battle high pollution levels with air quality swaying from "very poor" to "emergency" levels, restricting physical activity and forcing closure of schools.
The fine particles of urban pollution can damage the blood-brain barrier, the membrane that protects the brain from toxic substances, exacerbating the risk of Parkinson's disease and Alzheimer's disease in the elderly.
About 17 million babies worldwide live in areas where outdoor air pollution is six times the recommended limit, and their brain development is at risk, the United Nations children's agency (UNICEF) said on Wednesday.
In a statement Wednesday, UNICEF said that satellite imagery showed South Asia was home to the biggest proportion of babies - 12.2 million - living in the worst-affected areas. Also the report claimed that in East Asia and the Pacific, there are approximately four point three million babies who are breathing toxic air.
The air pollution level has been consistently 10 points above the safe zone.
When there is an exposure of a pregnant women to pollutants, it harms them a lot.
The report highlights the relationship between pollution and brain functions " like memory and verbal IQ and non-verbal, test results, lower scores among schoolchildren, as well as other neurological problems ".
The pollution " will impact the learning of the children, their memories, their language skills and motor", said to AFP Nicholas Rees, author of the report. "As yet, we know the minimum - but not the maximum - extent of the harm".
The World Health Organization describes air pollution as a "major environmental risk to health".
"As more and more of the world urbanises, and without adequate protection and pollution reduction measures, more children will be at risk in the years to come".
Lake called on countries exceeding worldwide limits to step up efforts to reduce air pollution.
The report sets out a range of ways that the impact of air pollution on babies' brains could be lowered.
It called for a greater use of masks, air filtration systems and for children to avoid travelling when pollution levels are at their highest.