From the skies above to the ground below, Delhi is polluted. This Indian territory, which includes the capital city of New Delhi, is half the size of Rhode Island, and is home to twice the population of New York City.

Beijing, China, often makes headlines for its polluted air, but a global study of air pollution in 2014 by the World Health Organization found that Delhi’s air contained several times more fine particulate pollution than Beijing’s. By most measurements, it’s the most polluted area in the world.

To get a glimpse of what it’s like to live in these conditions, photographer Matthieu Paley spent five days walking across Delhi. Through his photographs, we see the physical results of intense