Hume retired from the civil service in 1882. In 1883 he wrote an open letter to the graduates of Calcutta University, calling upon them to form their own national political movement. This led in 1885 to the first session of the Indian National Congress held in Bombay.
Hume was very outspoken and never feared to criticise when he thought the Government was in the wrong. In 1861, he objected to the concentration of police and judicial functions in the hands of the police superintendent. In March 1861, he took a medical leave due to a breakdown from overwork and departed for Britain. Before leaving, he condemned the flogging and punitive measures initiated by the provincial government as 'barbarous … torture'. He was allowed to return to Etawah only after apologizing for the tone of his criticism. He criticized the administration of Lord Lytton (before 1879) which according to him cared little for the welfare and aspiration of the people of India. Lord Lytton's foreign policy according to him had led to the waste of "millions and millions of Indian money". Hume was critical of the land revenue policy and suggested that it was the cause of poverty in India. His superiors were irritated and attempted to restrict his powers and this led him to publish a book on Agricultural Reform in India in 1879.