Corona discharge is a phenomenon that occurs when a high voltage is applied to a conductor, causing ionization of the surrounding air. This ionization creates a conductive path, allowing electric current to flow through the air, which can produce a visible glow and a hissing sound. It typically happens at sharp points or edges of the conductor, where the electric field is strongest. This effect is commonly observed in high-voltage power lines and electrical equipment. While corona discharge can lead to energy loss and electromagnetic interference, it is also utilized in various applications, such as air purification and electrostatic precipitators for pollution control.