Final answer:
The cause of Indian nationalism can be attributed to colonial policies and the formation of the Indian National Congress in 1885, aiming for political reforms and overcoming British barriers to industrialization. The promise of increased rights after World War I went unfulfilled, increasing nationalist movements, and eventually leading to acts granting more autonomy.
Step-by-step explanation:
Colonialism is often cited as the root cause of the rise of Indian nationalism. The disenchantment of Indians with British policymaking, particularly after events like the Sepoy Mutiny of 1857 and Britain's disregard for Indian support in World War I, led to the growing demand for self-governance.
British-educated Indians, who were expected to bolster British control, instead became the leaders of the nationalist movement. The Indian National Congress (INC), established in 1885 by moderate nationalists, was pivotal in articulating political reforms and pushing towards industrialization, which was hindered by British-imposed barriers.
In the aftermath of World War I, Indian hopes for increased rights and independence were dashed by the British reluctance to relinquish control, further fueling nationalist sentiments. By the early 20th century, broader movements and political parties like the INC and the Muslim League started seeking political leverage and independence, culminating in the 1935 India Act which was a step towards autonomy within the British Empire.