Short answers, pulled from the story.
Sidney Rowlatt chaired a committee appointed in 1917 to evaluate political terrorism and the Indian independence movement. The Imperial Legislative Council in Delhi hurriedly passed the Anarchical and Revolutionary Crimes Act on the 18th of March 1919.
The Rowlatt Act came into effect on the 21st of March 1919 across British India. Tensions ran high in Punjab leading to rioting in Delhi, Gujarat, and other regions following this implementation date.
Madan Mohan Malaviya resigned from the Imperial legislative council in protest against the new legislation. Muhammad Ali Jinnah and Mazarul Haque joined these resignations as part of a unified front against the act.
On the 10th of April two congress leaders Dr. Satyapal and Saifuddin Kitchlew were arrested secretly. They were taken to Dharamsala away from public view before people gathered for Baisakhi Day celebrations and to protest their deportation in Amritsar on the 13th of April.
The British colonial government repealed the Rowlatt Act in March 1922. This repeal followed the acceptance of a report from the Repressive Laws Committee alongside the revocation of numerous other laws including the Press Act and Sedition laws.