In 1920, the Treaty of Sevres established Iraq as a mandate of the League of Nations under British administration. However, the British mandate was terminated in 1932, and Iraq was admitted to the League of Nations on October 3, 1932. It was a joyful time in Baghdad and other parts of the country, with the majority of people rejoicing. The official Iraqi Independence day was marked to be celebrated on the same day.
The establishment of the League of Nations took place in 1920, at the end of the first World War, as an attempt at creating an international organization to solve disputes and maintain peace.
Here’s a picture of a parade being held in Baghdad in celebration of Iraq joining the League of Nations.