Survival skills
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
Water scarcity in Africa
Water scarcity or lack of safe drinking water is one of the world's leading problems affecting more than 1.1 billion people globally, meaning that one in every six people lacks access to safe drinking water. The Joint Monitoring Programme for Water Supply and Sanitation set up by the World Health Organization (WHO) and United Nations Children's Fund (UNICEF) defines safe drinking water as "water with microbial, chemical and physical characteristics that meets WHO guidelines or national standards on drinking water quality." Hydrologists generally assess water scarcity by looking at a population-to-water equation that treats 1,700 cubic meters per person as the national threshold for meeting water requirements for agricultural and industrial production, energy, and the environment. Availability below the threshold of 1,000 cubic meters represents a state of "water scarcity", while anything below 500 cubic meters represents a state of "absolute scarcity".