Without such particles, clouds would be rare: the air would need to be freakishly saturated with water vapour or strangely cold for condensation to occur.

ECONOMIST: Aerobiology

These are boxes containing air that is super-saturated with water vapour.

ECONOMIST: Global warming

Wetlands are ecosystems saturated with water, either seasonally or permanently.

UNESCO: UK National Commission for UNESCO - UNESCO Conventions, Recommendations & Declarations in the UK

Thames Water said rain and saturated ground left it with no choice but to constantly pump sewage away.

BBC: Thames Water spends ?4.5m fighting sewage floods