Baltic Sea dead zones
Gotland Deep, Sweden · 57.30°, 20.00° · River pollution
Nutrient runoff has created the largest human-caused oxygen-free seabed in the world.
The Baltic is shallow, brackish and slow to flush, so fertiliser and sewage from nine countries accumulate. Algal blooms sink and rot, leaving deep basins with no oxygen; the hypoxic area has been compared to the size of Denmark. HELCOM, a regional agreement, coordinates cuts to nutrient inputs.
In the game
Baltic Sea dead zones flares up as Polluted water. The fix is a gesture: drag through the floating waste to sweep it up. Done right, it becomes Water cleaned ♻️. Finish all three steps of its chain in one round for a combo, or take your time in Explore mode: a place you fully restore stays green on your map for good.
🧭 Fly there and restore it▶ Play a 60-second round