The Indian national flag, the Tiranga, has a rich history reflecting India's journey to independence. It evolved from various designs during the freedom movement, culminating in the current tricolor flag with the Ashoka Chakra. The flag was officially adopted on July 22, 1947, by the Constituent Assembly, just weeks before India's independence. 

Here's a more detailed look:
Early Designs:
In 1906, a flag was hoisted in Calcutta during the Swadeshi movement, and a similar flag was raised by Madam Bhikaji Cama in Paris in 1907. 
Home Rule Movement Flag:
In 1917, a flag was hoisted as part of the Home Rule Movement, symbolizing the demand for self-governance. 
Pingali Venkayya's Design:
In 1921, Pingali Venkayya presented a flag design to Mahatma Gandhi, featuring three stripes (red, green, and white) and a spinning wheel. 
Formal Adoption:
The current flag, with saffron, white, and green stripes and the Ashoka Chakra in the center, was adopted on July 22, 1947. 
Significance of Colors:
The saffron represents courage and sacrifice, the white signifies peace and truth, and the green symbolizes fertility and growth, according to the PIB. 
Ashoka Chakra:
The navy blue Ashoka Chakra, with 24 spokes, is taken from the Sarnath Lion Capital of Ashoka and represents the "wheel of law" and progress, says Know India.