Underwater noise due to human activities at sea can harm marine biodiversity, leading for example to hearing impairment and behavioural disturbances. EU experts have adopted recommendations on maximum acceptable levels for impulsive (for example from oil and gas exploration and extraction) and continuous (such as from shipping) underwater noise. The new limits mean, that to be in tolerable status, no more than 20% of a given marine area, can be exposed to continuous underwater noise over a year Similarly, no more than 20% of a marine habitat can be exposed to impulsive noise over a given day, and no more than 10% over a year. These underwater noise pollution limits deliver on the Zero Pollution Action Plan and are the first of this kind at global level. The threshold values will contribute to set limits on where and for how long marine habitats can be exposed to underwater noise. Impulsive underwater noise, such as from oil and gas exploration, occurs in about 8 % of the EU's seas: it is particularly present in large areas of the Baltic, North and Celtic Seas, and the Mediterranean area. Maritime traffic is the main source of continuous underwater noise. With 27% of its area subject to shipping, the Mediterranean Sea sees the highest shipping traffic in the EU. This is followed by the Baltic Sea (19 % of the area). Overall, only 9% of the EU's sea area has no shipping traffic. EU Member States will now need to take these threshold values into account when they update their marine strategies.