Knowledge discovery from emergency ambulance dispatch during COVID-19: A case study of Nagoya City, Japan

•Significant change is observed in emergence ambulance dispatches (AEDs) in Japan early 2020.•Accurate estimation of AED is required during COVID-19 pandemic for resources management.•A machine learning method for accurate EAD forecasting from environmental factors is proposed.•The use of mobile phone usage data can improve EAD forecasting during a pandemic.•The proposed method can successfully forecast EAD for different age and location categories.