A (pollution control unit) may pertain-to a transport-department.
Some problems can be constituted-of-or-filled-with pollution.
A main source can be constituted-of-or-filled-with pollution.
Fears can be constituted-of-or-filled-with (water pollution).
Legislation may set_up a (carbon pollution reduction scheme).
A world-city may use a classification of (air quality) on a basis of (pollution indices).
Some indicators can be constituted-of-or-filled-with pollution.