The Ashoka Chakra is a depiction of the dharmachakra; represented with 24 spokes. It is so called because it appears on a number of edicts of Ashoka, most prominent among which is the Lion Capital of Ashoka. The most visible use of the Ashoka Chakra today is at the centre of the Flag of India (adopted on 22 July 1947), where it is rendered in a navy blue colour on a white background, replacing the symbol of charkha (spinning wheel) of the pre-independence versions of the flag.

India's highest peacetime military decoration awarded for valour, courageous action or self-sacrifice away from the battlefield is also called Ashoka Chakra.

12 of the 24 spokes represent the twelve causal links taught by the Buddha and pratītyasamutpāda (conditional arising). The first 12 spokes represent 12 stages of suffering. Next 12 spokes represent no cause no effect. So, due to awareness of mind, formation of mental conditioning stops. This process stops the process of birth and death i.e. nibbana. The twelve causal links, paired with their corresponding symbols, are:

Avidyā ignorance -

Sanskāra conditioning of mind unknowingly

Vijñāna consciousness

Nāmarūpa name and form (constituent elements of mental and physical existence)

Ṣaḍāyatana six senses (eye, ear, nose, tongue, body, and mind) -

Sparśa contact -

Vedanā sensation -

Tṛṣṇā thirst -

Upādāna grasping -

Bhava coming to be -

Jāti being born -

Jarāmaraṇa old age and death - corpse being carried.

More Info: en.wikipedia.org