Question

Change in pressure is directly propotional to melting point of the substance. Then how does ice melt at lower temperature when pressure is increased during regelation?

Answer 1

Regelation is the phenomenon of melting under pressure and freezing again when the pressure is reduced. It only occurs for water-like substances that expand upon freezing or their volume increases as temperature decreases. For such substances the melting point decreases as pressure is increased, increasing pressure tends to cause excitation in surface atoms leading to melting.