March 23 is observed as Martyrs Day, also known as Shaheed Diwas or Sarvodaya Day.
It is celebrated as a tribute to martyrs Bhagat Singh, Sukhdev Thapar, and Shivaram Rajguru.
The trio fought for the freedom of India from the colonial rulers and sacrificed their lives on March 23, 1931, when they were hanged to death by the British.
They assassinated a British Police Officer to avenge for the lathi charge against Lala Lajpat Rai and his followers, who were protesting against the Simon Commission.
The case under which these martyrs were tried was later known as the Lahore Conspiracy Case.