People held protests at several places, including Hazratganj, Gomti Nagar, Aliganj and Vikas Nagar.
Shouting anti-graft slogans, people condemned the Delhi Police action against Hazare, who was detained Tuesday morning, hours before his planned fast against a proposed anti-corruption bill.
"It’s undemocratic...It’s all taking place at the behest of the central government, which is trying to gag every voice being raised against corruption," Meeta Singh, a housewife, who participated in a demonstration in Gomti Nagar, told reporters.
Holding the tricolour aloft, Hazare's supporters also played patriotic songs.
“In a democracy like ours, one has the right to protest in a peaceful manner. By detaining Hazare and others supporting him, the government is depriving the country’s citizens of their constitutional rights," P.K. Garg, a retired professor, told reporters in Hazratganj.
Members of India Against Corruption, which has been backing Hazare, will also stage a sit-in at the Jhulelal Park here.
Residents of various localities will also be taking out candle marches in support of Hazare.