Music naturally contains rhythm but rhythmical structures that is taal is the speciality of Indian classical music and dance. Rhythm is the regular movement of time in music and rhythmical structures are manifested on it when it occurs in the form of a cluster of actions. Number of beats represent taal while size of the beat shows rhythm.
Taal is to embellish the rhythm. Rhythm is continuesly going on and taal is imposed on it to beautify and to understand clearly this regular movement of time. Taal divides rhythm in different equal segments which are further divided into different equal or unequal parts according to the taal imposed on it. For eg:
If taal is teentaal then rhythm is divided into equal segments of 16 beats further divided into four equal parts of four beats each.
If taal is dhamaar then rhythm is divided into equal segments of 14 beats further divided into four unequal parts.
All Indian Classicad Dances are based on rhythm and taal. Folk dances and bollywood dances are based on rhythm.