Brass Sun Chariot with 7 Horse, Lord Surya Rath

Surya is a Sanskrit word that means the Sun. The iconography of Surya is typically shown as a resplendent standing person holding sunflower flower in both his hands, riding a chariot pulled by Seven Horses which represent the seven colours of visible light, and seven days in a week.
Sun is the source of light and that is white light (VIBGYOR) =white Violet + indigo + blue + green +yellow + orange + red ==white So all 7—horses represent each colour of the VIBGYOR. It is the seven colours of the sun light which reach us on our earth give us warmth , sustain our life and balance our solar system.

In medieval Hinduism, Surya is also an epithet for the major Hindu gods Shiva, Brahma and Vishnu. The oldest surviving Vedic hymns, such as the hymn of the Rigveda, mention Surya with particular reverence for the "rising sun” and it's symbolism as dispeller of darkness, one who empowers knowledge, the good and all life.

Earliest representations of Surya riding a chariot occur in the Buddhist railings of the Mahabodhi temple in Bodhgaya (2nd cent. BCE), in the Bhaja Caves (1st cent BCE), and the Ananta Gumpha at the Khandagiri caves (1st cent. CE).
The seven horses are named after the seven meters of Sanskrit prosody: Gayatri, Brihati, Ushnih, Jagati, Trishtubha, Anushtubha and Pankti.

The Sun Chariot illustrates the idea that the sun was drawn on its eternal journey by divine horses. A sun image and the horse have been placed on wheels to symbolize the motion of the sun.