According to the passage, which issue propelled Gandhiji to the national stage for a wider movement?

Gandhi's speech in Banaras in February 1916 was, at one level, merely a statement of fact, namely that Indian nationalism was an elite phenomenon, a creation of lawyers and doctors and landlords. But at another level it was a statement of intent, the first public announcement of the returning expatriate's own desire to make Indian nationalism more properly representative of the Indian people. In the last month of that year, Gandhi was presented with an opportunity to put his precepts into practice. At a meeting held in Lucknow in December 1916, he was approached by a peasant from Champaran in Bihar, who told him about the harsh treatment of peasants by British indigo planters. Gandhi spent most of 1917 in Champaran, seeking to obtain for the peasants security of tenure as well as the freedom to cultivate the crops of their choice. In 1918 Gandhi was involved in two campaigns in his home state of Gujarat: first he intervened in a labour dispute in Ahmedabad to better the conditions of textile mill workers, and then he joined peasants in Kheda seeking remission of taxes after the failure of their harvest. These initiatives marked Gandhi as a nationalist with sympathy for the poor, though they were local struggles. During the First World War the British had instituted press censorship and permitted detention without trial, and the Rowlatt committee recommended the continuation of these tough measures. Gandhi's call for a countrywide campaign against them brought life to a standstill in north and west India.