The Ashoka Chakra is a depiction of the Dharmachakra. It is called so 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. It is also shown in the Ashoka Chakra medal which is the highest award for gallantry in peacetime.
When Gautama Buddha achieved enlightenment at Bodh Gaya, he came to Sarnath. There, he found his five disciples Assaji, Mahānāman, Kondañña, Bhaddiya and Vappa, who had earlier abandoned him. He introduced his first teachings to them, thereby establishing the Dharmachakra;. This is the motif taken up by Ashoka and portrayed on top of his pillars.
The 24 spokes represent the twelve causal links taught by the Buddha and paṭiccasamuppāda (Dependent Origination, Conditional Arising) in forward and then reverse order. 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. nibbāna. It also depicts the “wheel of time” . The twelve causal links, paired with their corresponding symbols, are:
These 12 in forward and reverse represent a total 24 spokes representing the dhamma. The Ashoka Chakra is depicting the 24 principles that should be present in a human.
Ashoka Chakra was included in the middle of the national flag of India.In fact, in 1942, in Varanasi, when Mohan Malviya invited Mahatma Gandhi to the Golden Jubilee celebrations of the university, Mahatma Gandhi also visited Sarnath. There he saw the Ashoka chakra . After this Gandhi used the Ashoka Chakra in the wheel of the flag. The flag with a spinning wheel with 24 spokes led the Quit India Movement of 1942. The chakra intends to show that there is life in movement and death in stagnation. Dr B. R. Ambedkar was instrumental in reviving the legacy of Ashoka, and using the Ashokan Wheel on the flag was one of the ways where he tried to memorializing the Buddhist king.