Why children are thrown from the hight of 15 meters in India?

In some of the Indian villages there is an old tradition of throwing new born babies form the top of the tower. For example, in the village Musti, Maharatsha state, new born babies are thrown from the hight of 15 meters. They explain that this ritual will bring them health and strength.

SOURCE: http://edition.cnn.com/2008/WORLD/asiapcf/05/01/babies.tower/
IMAGE: www.anvari.org