Seeing is deceiving...
I ran across this photo on Neatorama, captioned "Pollution - what pollution?"
Exactly correct. These are cooling towers, perhaps for the Ferrybridge Power Station in West Yorkshire, England. Cooling towers have water running through them and by evaporation and conduction provide the heat sink necessary to run the steam cycle for steam turbines. There are no combustion products, stack gases, or smoke emitted from cooling towers. (The actual "smokestacks" can be seen just to the right, I think.)
In fairness, heat could be seen as a type of pollution, but even the most stringent definition would hardly place water vapor in that category.
Cooling towers have become iconic for nuclear power and the mythical risks associated with them. Ironically, they could be the least hazardous part.