A solution that contains the maximum amount of solute at a given temperature is called a saturated solution, and the amount of solute present in a saturated solution at a given temperature is called solubility. Solubility is directly proportional to temperature. So, when temperature decreases (i.e., when the saturated solution is cooled), solubility also decreases. On cooling the saturated solution, its solubility decreases which result in the separation of some of the dissolved substance or solute in the solid crystal form.Therefore, the solution becomes supersaturated.