Disaster refers to the negative impacts of natural or human-made hazards on society and the environment. The word's roots come from astrology and the idea that bad events occur when stars are in poor positions. Disaster management involves preparing for, responding to, and recovering from disasters to avoid or lessen their impacts. Effective emergency management relies on integrating plans across all levels of government and non-government groups, as actions at each level affect the others. Disaster management aims to deal with and reduce risks from a variety of disaster types.