India at 75: How did India adopt the Tricolour as its national flag?

Tricolour has evolved over several decades. The Indian flag is said to have been designed for the first time by Sister Nivedita; however, its present form was designed by Pingali Venkayya

A national flag is a symbol of the sovereignty and independence of a country. Indians have always held the Tricolour in high esteem. It played an important role not only in the freedom struggle but even in the post-independence wars, including the Indo-China war and the Kargil War. 

To honour the Tricolour on the 75th Independence day, the Indian government has decided to organise the 'Har Ghar Tiranga' campaign under 'Azadi Ka Amrit Mohatsav'. Between August 13 and 15, 200 million will be hoisted atop schools, offices and even houses across the nation. 

How was the Tricolour chosen as India's