Rangoli is an art form originating in the Indian subcontinent especially in Maharashtra and Karnataka, in which patterns are created on the floor or a tabletop using materials such as powdered limestone, red ochre, dry rice flour, coloured sand, quartz powder, flower petals, and coloured rocks. It is an everyday practice in Hindu households for plain white rangolis, however, colours are preferred during festivals and other important celebrations. Rangolis have different names based on the state and culture.

Rangolis are usually made during Diwali or Tihar, Onam, Pongal, Sankranthi, and other Hindu festivals in the Indian subcontinent, and are most often made during Diwali in Maharashtra. Designs are passed from one generation to the next, keeping both the art form and the tradition alive. The rangoli represents the happiness, positivity, and liveliness of a household, and is intended to welcome Lakshmi, the goddess of wealth and good luck. It is believed that a Hindu household without a clean house entrance and a rangoli is considered as an abode of 'darida' (bad luck).

More Info: en.m.wikipedia.org