why did Gandhi go to Lucknowin 1916?what happened there that was to change the course of Indian history

Gandhi had gone to Lucknow in December 1916 to attend the annual convention of the Indian National Congress party. There he met a peasant who came up to him looking like any other emaciated and penurious Indian peasant and introduced himself as Rajkumar Shukla from Champaran. Shukla wanted Gandhi to come to his district, a place Gandhi had never heard of but was situated in the foothills of the towering Himalayas, near the kingdom of Nepal. This was the meeting that Gandhi recalled as the decisive factor which changed the course of the political history of India and urged Gandhi to seek the departure of the British from India.