Overall Water Pollution Levels Worldwide
This is a puddle, that has been contaminated. If you go outside, you will often notice these in parking lots, industrial areas, and in large grassy areas. This is a sign of water pollution. It's not hard to guess why parking lots and industrial areas will often have this. They both receive runoff from large cities where there is pollution from chemicals humans use. The grassy areas can have this because of pesticides people will put in the grass, to keep it green and healthy.