Sthapana and Visarjan of Ganesh idols symbolise the cycle of life and death, impermanence and constant change. The idols are immersed in water just like the ashes of the deceased are immersed in the river after the cremation. The sthapna and visarjan are both done with equal fervour to encourages us to celebrate both life and death as the soul never dies. It returns back just like the Ganeshji a year later.