A state of emergency is a special situation created for the purpose of allowing a government to put through policies that it might not normally be allowed to do, and which would allow it to respond to an event or threat. The term is usually used in relation to a natural disaster, civil unrest, armed conflict, or medical pandemic or epidemic, but can also be applied to a variety of other situations.
A declaration of state of emergency allows a government to infringe the freedoms of the citizens (such as the right to free speech or movement), and it can also give that government the power to close public buildings, impose curfews, censor the media, and otherwise restrict activities and people to protect the population. This is often accompanied by martial law, in which military forces are deployed to control unrest and the safety of civilians.
States have different definitions of emergencies, and in some cases the state of emergency is not defined at all, in which case a Governor can declare it whenever they see fit. In other countries, there are specific statutory provisions that set out when a state of emergency can be declared, or in some cases only certain types of emergencies can be invoked under a state of emergency.
Some states have specific procedures for requesting a declaration, and in some cases a request must be approved by the national government (for example, France). In other countries, particularly those with a dictatorship style government, a state of emergency can be abused to suppress opposition, for example by giving the government the power to act without needing to comply with the constitution or other human rights laws.