Why are the East sides of former industrial cities like London or New York poorer and more deprived? We argue that this is the result of wind patterns. At the latitude of the U.S. and Western Europe, predominant Westerlies blow from West to East and caused higher concentrations of industrial pollution in the east side of cities. To capture this empirically, we geolocate nearly 10,000 industrial chimneys in 70 English cities around the year 1880 and use terrain and wind patterns to predict where their smoke would have drifted. Individual-level census data for 1881 show that pollution induced neighbourhood sorting with the working class population residing in the East. These equilibria persist to this day. Historic pollution patterns explain up to 20% of modern within-city deprivation even though the pollution that initially caused it has now waned.