Pollution from traffic is driving an asthma crisis in India’s children, a new study suggests.
Exposure to traffic-related air pollution (TRAP) contributes to 350,000 new cases of childhood asthma in India every year, estimates a research paper published today in The Lancet. This is the second highest burden of new TRAP-related cancer cases in the world, after China.
Globally, the study estimates that four million cases of asthma in children can be attributed to traffic pollution. This accounts for thirteen percent of the global asthma burden in children.
What is worth noting is that India actually ranked at the bottom of the list of the 125 countries studied in terms of TRAP-related childhood asthma incidence and was placed 58th in terms of proportion of asthma cases attributable to TRAP. This highlights the fact that India’s superlative paediatric population means that even health threats of low incidence still translates to an effect on the quality of life for hundreds of thousands of youth. Of the Indian cities profiled, those with the highest incidence of traffic pollution-related asthma per 100,000 children were Ahmedabad (150); Bengaluru and New Delhi (both 140); and Mumbai (130).
Concerningly, the study notes that even exposure to levels at or below World Health Organisation (WHO) guidelines concerning nitrogen dioxide (NO2), a major component of TRAP, can be harmful. The WHO states that exposure to NO2 should not exceed 40 μg/m3 (or 21 parts per billion), the study notes.
“Our findings suggest that the World Health Organization guidelines, for annual average NO2 concentrations might need to be revisited, and that traffic emissions should be a target to mitigate exposure,” the study’s senior author Dr Susan Anenberg remarked.
Professor Rajen N. Naidoo concurred with Dr Anenberg’s assessment, commenting that ““An important outcome from this study is the further evidence that the existing WHO standards are not protective against childhood asthma.” Professor Naidoo noted that “approximately 92% of the childhood asthma incidence attributable to NO2 exposure was in areas with NO2 concentrations below the values of the WHO annual average guidelines” and asserted that “this strengthens the case for the downward revision of these global standards and for stronger national policy initiatives in countries without air quality standards.”
TRAP is a major contributor to outdoor air pollution, caused by the combustion of fossil fuels in the engines of vehicles. Approximately 230 million vehicles were on the road in India in 2016. In seven states, there are more than ten million registered vehicles as of 2015 – a number likely to have risen in the years since, as seen in the fact that the number of registered vehicles in India jumped by around twenty million between 2015 and 2016.
Congestion is a major issue across a number of Indian cities, which in turn has a deleterious effect on air quality and increases vehicle emissions. In the most heavily congested city Mumbai, there are 510 cars for every kilometre.
The study is yet another reminder of the negative health effects of air pollution, one of the major public health crises facing modern India.
1.2 Indians million people lost their lives to the effects of air pollution in India in 2017 alone, with seven of the world’s ten most polluted cities situated in India. For child health, the effects of pollution are particularly damaging. 93 percent of children worldwide are exposed to toxic air. In south Asia, children born today will lose two years and six months of their life expectancy.
The ubiquity of India’s air pollution menace is particularly bad news for asthma sufferers. One tenth of the world’s asthma patients live in India as previously reported by Health Issues India. Air pollution carries dire implications for them – and, even more worryingly, is creating a whole new generation of sufferers who, thanks to what contributed to their condition in the first place, are vulnerable to suffer even further.
The Lancet study, “Global, national, and urban burdens of paediatric asthma incidence attributable to ambient NO₂ pollution: estimates from global datasets”, can be accessed here.