Ganesh Chaturthi is celebrated on the birthday of Lord Ganesh (Ganesha), the god of wisdom and prosperity on the fourth day of the moons bright fortnight, or period from new moon in the lunar month of Bhadrapada. The celebration of Ganesh Chaturthi continue for five, seven, or ten days.
Some even stretch it to twenty one days, but ten the most popularly celebrated. In the tradition of the right hand path the first day is the most important. In the left hand path tradition the final day is most important.