According to the World Health Organization (WHO), air pollution is the world’s single biggest environmental health risk. In high concentrations, ultra-fine particulates can cause strokes, heart disease, lung disease and some cancers. Last year, the WHO reported that air pollution caused 7.8 million premature deaths worldwide, 1.5 million of which were in Delhi. Due to the city’s dangerously high levels of ultra-fine particulates, Delhi has since been dubbed by the WHO the most polluted megacity on Earth.
The factors contributing to these high levels are being investigated in a study published in Atmospheric Environment. Dr Prashant Kumar, reader of urban air quality at the University of Surrey and lead author says ‘while it might be easy to blame this on the increased use of vehicles, industrial production, or a growing population, the truth is that Delhi is a toxic pollutant punchbowl with myriad ingredients, all which need addressing in the round.’
He says that an overlooked part of the issue could be the city’s geography. Being landlocked, Delhi is unaided by the winds that shift pollution in coastal cities such as Chennai, which has ten times as many vehicles. According to the study, other factors could be the city’s architecture of densely-packed buildings, which prevent air circulation, as well as the fact that pollution is decreasing the city’s air temperature, causing it to draw in yet more polluted air from the outskirts. Kumar says windy, dusty conditions during the summer months also worsen the problem.
‘Factors outside of human control – such as Delhi’s climate and weather patterns – compound the effects of human behaviour,’ Kumar tells Geographical. ‘Given the complexity of sources, the influence of meteorology and influx from peripheral areas, Delhi’s pollution cannot be managed independently, only on a city-wide scale. But it requires an integrated approach including the adjacent peripheral regions.’
Kumar feels that in order for climate mitigation to be effective in a developing city such as Delhi, air quality must be considered in a broader framework of economic development: ‘It is a complicated, pick-and-mix of problems that will prove difficult to combat without innovative, encompassing and quick action.’