The hazes in Southeast Asia have become an increasingly frequent occurrence and can spread across many countries, causing serious health and safety concerns. It can be hazardous to even go outside, so often cities will shut down, adding economic costs to the list of consequences.
NASA has published these two images of the Aral Sea, which used to be the fourth biggest lake in the world before the Soviet Union plugged into the rivers that fed it to irrigate massive agricultural areas. The photo on the right was taken in 2000. On the left you can see its current state.