Air pollution is one of the big drivers of climate change. As well as being a principal source of greenhouse gas emissions, the transport sector is responsible for a large proportion of urban air pollution.

The World Health Organisation estimates that outdoor air pollution leads to 4.2 million premature deaths globally through cardiovascular and respiratory diseases, cancer, and adverse birth outcomes. For example, a recent study found that even a small increase in air pollution can make coronavirus more deadly. This is particularly concerning as 91% of the world’s population currently live in places where air quality exceeds World Health Organisation guideline limits.

These photos were taken in the Ethiopian capital Addis Ababa - a very congested city where cars, minibuses, people, trucks, and dogs fill the streets. Traffic-busy streets, and increasing pollution, are indicators of Ethiopia’s impressive economic growth over the past two decades. This growth has seen income poverty more than halve, with huge advances in human development outcomes, and without substantially increasing income inequality. Yet a flipside to growth is that air pollution is becoming a serious health problem in Ethiopia’s cities and big towns.