Dark Smog is a Continuous Trap Card.
Trap Cards are normally Set first and can be activated on a later turn, often in response to an action.
On the current TCG and OCG Forbidden & Limited lists tracked here, Dark Smog is Unlimited.
YGOPRODeck lists Dark Smog for these formats: Duel Links, Speed Duel, Common Charity, TCG, OCG, Master Duel.
A listed print of Dark Smog appears in Abyss Rising: Special Edition (ABYR-ENSE2) at Super Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Dark Smog is about $0.08 on Cardmarket (prices change frequently).
