How did colonies in South Asia and the Middle East participate in World War I?
With the onset of WWI, the French and the British sent armies and agents into the Middle East, to foment revolts in the Arabian Peninsula and to seize Iraq, Syria, and Palestine. In 1916, French and British diplomats secretly reached the Sykes-Picot agreement, carving up the Middle East into sphere of influence for their respective countries. That agreement was superceded by another which established a mandate system of French and British control, sanctioned by the new League of Nations. Under he mandate system, Syria and Lebanon went to French, the British took over Palestine and the three Ottoman provinces of Mesopotamia and created the modern-day Iraq.
Asia. Of all the Asian countries involved in World War I in some manner, India, a colony of the British Empire at the time, sent the most: 1.3 million troops and laborers went to the imperial war effort. China was officially neutral but provided about 200,000 laborers to the Allied forces to repair tanks. Japan entered the war on the side of the Allies on 23 August 1914, seizing the opportunity of Imperial Germany's distraction with the European War to expand its sphere of influence in China and the Pacific. Japan already had a military alliance with Britain, but that did not obligate it to enter the war.