The Anarchical and Revolutionary Crimes of 1919 (popularly known as the Rowlatt Act) was a law passed in 1919 by British India. Under this law, the government got many powers, including the ability to arrest people and keep them in prisons without a trial. They also obtained the power to stop newspapers from reporting and printing news. The people called this act the Black Act. Indians protested against this law in many places. Fortunately this act was stopped by Mahatma Gandhi.
This exploited their right to protest. They could be arrested without trial. So, Indians hated it as it couldn't let them carry on their independence revolution