In ancient India, the Hindu schools of Samkhya and Vaisheshika, developed theories on light.
According to the Samkhya school, light is one of the five fundamental "subtle" elements (tanmatra) out of which emerge the gross elements.
The basic atoms are those of earth (prthivi), water (pani), fire (agni), and air (vayu).
Light rays are taken to be a stream of high velocity of tejas (fire) atoms.
The particles of light can exhibit different characteristics depending on the speed and the arrangements of the tejas atoms.
The Vishnu Purana refers to sunlight as "the seven rays of the sun".
The Indian Buddhists, such as Dignāga and Dharmakirti,
developed a type of atomism that is a philosophy about reality being composed of atomic entities that are momentary flashes of light or energy.
They viewed light as being an atomic entity equivalent to energy.
