C40 is a global network comprising nearly 100 mayors from leading cities, united in their commitment to tackle the climate crisis. The organization aims to reduce greenhouse gas emissions and climate risks while enhancing the health and economic opportunities of urban populations. The network is governed by a rotating steering committee, currently co-chaired by the mayors of London and Freetown. C40 provides technical assistance, facilitates exchanges among peers, and conducts research to bolster cities' climate action initiatives. C40 also runs various programs, including High-Impact Accelerators for transformative actions and the Reinventing Cities competition to promote sustainable urban development. Its knowledge hub serves as a vital resource for climate solutions and best practices for city leaders and policymakers.