In response to the climate crises, Societies of Anaesthesiology around the globe call for action to reduce the carbon footprint of daily clinical work. They recommend the use of regional and total intravenous anaesthesia, and for inhalational anaesthesia cases, the use of sevoflurane with low fresh gas flow (FGF \< 0.5 lpm) settings. Surprisingly, the type of anaesthesia and ventilation settings commonly used remain largely unknown. This pragmatic observational cross-sectional assessment at all anaesthesia workstations in participating European hospitals in daily routine aims to evaluate anaesthesia practices in the paediatric and adult patient population.