Solution

• Jallianwala Bagh Massacre (1919):
  The massacre occurred on 13th April 1919 in Amritsar, where British troops under General Dyer fired on a peaceful gathering, killing hundreds.

• Komagata Maru (1914):
  This incident involved a Japanese ship carrying Indian immigrants being denied entry to Canada, symbolizing racial discrimination under colonial policies.

• Jaito Morcha (1924):
  This was a Sikh agitation for the restoration of Maharaja Ripudaman Singh of Nabha, who was deposed by the British.

• Nankana Sahib (1921):
  The massacre at Nankana Sahib occurred when Sikh reformers were killed while trying to liberate gurdwaras from corrupt mahants during the Gurdwara Reform Movement.