World Meteorological Organization (WMO) is a specialized agency of the United Nations. It assists in the formation of worldwide networks for the observation of weather, climate, water levels, and other physical conditions of the earth. The organization also helps make weather information available for use in such activities as aviation, shipping, water management, and agriculture. WMO helps develop and manage early-warning systems for drought, cyclones, floods, ozone-layer depletion, and the movement of air pollution across national boundaries. In addition, the organization helps nations set up or improve their weather forecasting services.