"Our demand is to bring change in the present system, end corruption and take steps to bring back black money stashed away abroad," Sajal Nag, spokesman for the five organisations, said here.
Nag said the nine-hour hunger-strike would continue till 6:00 pm.
The protesters shouted slogans against the government's alleged indifference to corrupt practices, tougher steps to end the evil and steps for bringing black money stashed away in foreign banks.
The protesters criticised the Delhi police for the midnight crackdown on a rally by Ramdev at the Ramlila Maidan on June 6 last year.
The other organisations were Yuva Bharat, Kisan Panchayat and Mahila Patanjali Yoga Samiti.
Police were deployed near the venue of fasting at Metro channel in Esplanade area.