Which diving condition could increase the risk of decompression sickness?

Diving at high altitudes increases the risk of decompression sickness due to the change in ambient pressure compared to sea level. As a diver ascends to high altitudes, the atmospheric pressure decreases, which affects the behavior of gases dissolved in the body, particularly nitrogen. Under high pressure during a dive, nitrogen is absorbed into the body's tissues. If a diver ascends rapidly to a high altitude, the decrease in pressure can cause nitrogen bubbles to form, leading to decompression sickness.

In contrast, the other diving conditions, like diving in warm water or with high visibility, do not inherently affect the nitrogen absorption and elimination process in the same way. Diving with an excess air supply doesn't directly influence the risk of decompression sickness; instead, it's crucial to manage the mix and pressure properly during ascents to mitigate risks. Therefore, high altitude diving poses a unique risk related to pressure changes that can lead to this condition.