Traffic-related pollution caused asthma among 350,000 children in India in 2015, second only to China, according to a Lancet study released on Thursday. The damage to children\u2019s health is not limited to China and India though. In British and American cities, better off in terms of development and economic growth, the Lancet researchers blame traffic pollution for a quarter of all new childhood asthma cases. Canada has the third highest rate of new traffic-related asthma cases among the 194 nations analysed, while Los Angeles and New York City are in the top 10 worst cities out of the 125 assessed. With 92% of cases developing in areas that have traffic pollution levels below the World Health Organization (WHO) guideline level, the researchers suggest that this limit may need to be reviewed. The researchers used NO2 as a surrogate for the traffic pollution mixture as the gas is a pollutant formed mainly from fossil fuel combustion, and traffic emissions can contribute up to 80% of ambient NO2 in cities. Also read | MSMEs out of the woods? Credit improves, NPAs fall as small businesses turn around South Korea (31%) had the highest proportion of traffic pollution-attributable childhood asthma incidence. India ranks 58th for this metric because, although levels of other pollutants in the country are amongst the highest in the world, NO2 levels (between 2010 and 2012) in Indian cities appear to be comparable with better-placed European and US cities, the researchers said. Two-thirds of traffic pollution-related asthma cases occurred in urban centres globally, and when suburbs were included, this proportion increased to 90%. Therefore, policies tackling air pollution at city, state and national levels are needed, especially in the urban metropolitan areas. Although some countries and cities are pledging to phase out internal combustion engines and policies such as London\u2019s new ultra-low emission zone are being rolled out, this transition needs to become global, and it needs to happen faster. Else, the health of future generations will be compromised at birth.