Named after the chairman of the sedition committee, Sir Sidney Rowlatt, the Rowlatt Act was a law passed by the British in colonial India in March 1919 giving the imperial authorities power to deal with revolutionary activities. The act indefinitely extended wartime "emergency measures" in order to control public unrest and prevent plots for independence. Also known as the Black Act, it authorized detention without trial of any person suspected of terrorism, silenced the press and banned large public gatherings or protests.
The Act agitated many in the Indian Nationalist Movement, including Mahatma Ganhdi, who encouraged non violent civil-disobedience of the British Government by all Indians. The reaction against the act reached its climax with the Amritsar Massacre on 13 April 1919 (see below).