BEST-Cities is designed to provide city authorities with strategies they can follow to reduce city-wide carbon dioxide (CO2) and methane (CH4) emissions. The tool assesses local energy use and energy-related CO2 and CH4 emissions across nine sectors (i.e., industry, public and commercial buildings, residential buildings, transportation, power and heat, street lighting, water & wastewater, solid waste, and urban green space), giving officials a comprehensive perspective on their local carbon performance.