Which steel plant emits the most CO₂ in the world?
POSCO Gwangyang steel plant in South Korea is the world's highest-emitting steel plant, at roughly 34.8 million tonnes of CO₂e per year — more than the single dirtiest power station on Earth. Other top steel emitters include Angang Steel Co Ltd (~31 Mt) and Wuhan Iron and Steel Co Ltd (~26 Mt).
Highest-emitting steel plants (CO₂e/yr)
Source: Climate TRACE v6 (CC BY 4.0). Modelled estimates.
Why steel emits so much
Steelmaking is carbon-intensive by chemistry, not just fuel: a blast furnace releases CO₂ from coke acting as a chemical reductant, before counting energy. These are process emissions — you can't fix them by greening the electricity alone, which is why hydrogen direct-reduction and scrap-fed electric-arc furnaces ("green steel") matter.
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Frequently asked questions
What is the most polluting steel mill?
POSCO Gwangyang steel plant (South Korea) at ~34.8 Mt CO₂e/yr.
Does a steel plant emit more than a power plant?
Yes — POSCO Gwangyang steel plant (~34.8 Mt) out-emits the world's single dirtiest power station (~29 Mt).
How is this measured?
Modelled estimates from Climate TRACE (CC BY 4.0), not audited stack data — directional, not tonne-perfect.