What is the best known Hindu holy day festival?

India is a vast nation with regional festivals during harvest and other religious festivity.

Diwali is the festival of light.

Holi is the festivals of colour.

Baishaki is harvest festival in the north.

Pongal/Onum is harvest festival in the south.

Bihu is harvest festival in the east.

Ganesh festival for the god ganesh.

Ramzan/Id festival of the Muslims.