close up

high

equipment

outdoor

environment

plant

energy

industrial

power

technology

gray

heavy

smoke

smog

construction

industry

tower

ecology

toxic

two

complex

global

work

heat

tube

fuel

dirty

chemical

freight

Pollution

atmosphere

china

manual

trail

thick

lighting

pipe

gas

cooling

factory

dioxide

furnace

refinery

thermal

foundry

metallurgy

metallurgical

blast furnace

magnesite