New Delhi, Oct 10 (UNI) Police on Saturday detained hundreds of protesters on Saturday, including Abhijeet Dipke, founder of the youth outfit Cockroach Janta Party (CJP), TMC chief Mamata Banerjee, economist Jeanne Dreze, besides dozens of political and social activists, in a bid to thwart a protest at Jantar Mantar, the iconic medieval era stone-built set of astronomical instruments, demanding the resignation of Gyanesh Kumar, the country's chief election commissioner.