1.3 Critical infrastructure Societies worldwide depend on functioning infrastructure services, such as water, electricity, or telecommunication, which also facilitate the operation of the critical systems, such as transport and health systems. Such infrastruc- tures are referred to as critical infrastructures (CI), as they are considered system-relevant and essential for the functioning of a society. Governance Transport & Traffic Water Energy Food Finance Health IT & Tele communication Media & Culture The term critical infrastructure refers to physical structures (e.g., roads, internet, hospitals, power lines, water, and sewage network) and services provided (e.g., supermarkets, transportation, medical treatment), including the skilled work- ers required for these services. These complex and interconnected systems have become so ubiquitous and essential to day-to-day life that they are easily taken for granted. Our depend- ence on these systems is oftentimes disregard- ed until the services provided by such infra- structure are interrupted, for example, when we lose access to electricity, transportation, or wa- ter due to a severe storm or flooding. Generally, whenever critical infrastructure is disrupted or damaged, it considerably impacts a large part of the population, the economy, and the state. Critical infrastructures are characterized by a high degree of interdependence, which means that the impairment or failure of a single critical infrastructure can affect systems within the sector or spread to other sectors. The health sector, for example, relies heavily on the smooth supply of water and electricity, the transport sector on the provision of fuel and road accessibility, meanwhile the food industry depends on the transport and water availability. By “spilling-over” into another sector, any set- back or failure in one of these infrastructure systems can detrimentally affect public admin- istration, economic activities, reliability of supply, the welfare of communities, and public health, among others. Due to the changing risk landscape, major disruptions can occur even in countries with exceptionally reliable infrastructure systems. Additionally, the resilience and vulnerability of individuals and communities against disruption varies — for marginalized and dis advantaged parts of the population, a disruption of basic services might result in more severe social or economic repercussions. As the failure of critical infrastructure disproportionately affects more vulnerable people, it is also crucial to consider the needs of different population groups when strengthening critical infrastructure resilience. BBK, 2023 Promoting resilient critical infrastructure for risk-informed and sustainable development 16