Why was the Indian National Congress formed?

Founded in 1885 by members of the occultist movement Theosophical Society: Allan Octavian Hume, Dadabhai Naoroji, Dinshaw Wacha, Womesh Chandra Bonnerjee, Surendranath Banerjee, Monomohun Ghose, Mahadev Govind Ranade and William Wedderburn, the Indian National Congress became the leader of the Indian Independence Movement, with over 15 million members and over 70 million participants in its struggle against British rule in India. After independence in 1947, it became the nation's dominant political party, led by the Nehru-Gandhi family for the most part; major challenges for party leadership have only recently formed.