The costs of the protracted war in money and manpower were great. High casualty rates in the war, increasing inflation after the end, compounded by heavy taxation, the deadly 1918 flu pandemic, and the disruption of trade during the war escalated human suffering in India. The pre-war Indian nationalist sentiment was revived as moderate and extremist groups of the Indian National Congress ended their differences to unify. In 1916, the Congress was successful in establishing the Lucknow Pact, a temporary alliance with the All-India Muslim League. British political concessions and Whitehall's India Policy after World War I began to change, with the passage of Montagu–Chelmsford Reforms, which initiated the first round of political reform in the Indian subcontinent in 1917. However, this was deemed insufficient in reforms by the Indian political movement. Mahatma Gandhi, recently returned to India, began emerging as an increasingly charismatic leader under whose leadership civil disobedience movements grew rapidly as an expression of political unrest.