It's worth noting that "green steel" (wherein the iron ore is "reduced" to metallic iron using green hydrogen instead of syngas) is really only clean in places like Sweden which have clean electricity (theirs is  from nuclear and hydro).  In places like the US and Germany, the electricity is still way too dirty (using grid power with RE certificates is a rather phony solution). 

I've seen European proposals to make clean hydrogen using off-grid wind-farms. That's a clean solution, but very expensive, since it means running those expensive electrolysis units at the low capacity factor of European windpower.  It would actually be better for air pollution to use the windpower to displace more coal-fired electricity, and use fossil gas to make the iron.

Note also that this is definitely not the first steel made without coal.  Iron ore is reduced using carbon-monoxide in a blast-furnace or syngas (a carbon-monoxide and hydrogen mixture) in a direct-reduction furnace, and syngas can be made from coal or fossil gas.  Surely there are many places (e.g. the Middle East) where fossil gas is cheaper than coal.