Yes, Air Traffic Control (ATC) has the authority to declare an emergency on your behalf if they believe the safety of the flight is in jeopardy, even if you haven't explicitly used the words "Mayday" or "Emergency." This usually happens when a controller observes a critical flight profile change, such as a rapid unplanned descent, loss of communication, or a pilot sounding significantly distressed or incapacitated. In 2026, safety protocols emphasize that controllers should "err on the side of caution" to provide priority handling and alert emergency services. However, as a pilot, it is always a "pro-tip" to declare it yourself; this clearly establishes your needs and prevents any ambiguity. Once an emergency is declared—either by you or ATC—you are granted "emergency authority" to deviate from any regulation or instruction to the extent required to meet the emergency and land the aircraft safely.