Patkar has alleged that Mumbai's Slum Rehabilitation Scheme was marred by corruption, government indifference and builders' atrocities.
Patkar has demanded that work on the six Slum Rehabilitation Authority projects be stopped till the enquiry in the matter was completed.
Many people faced evictions and some of the houses in areas like Golibar were demolished to make way for slum rehab projects.
An associate of Patkar said the National Human Rights Commission has issued notices to the Chief Secretary and DGP of Maharashtra, calling for their response to the issues of demolitions and the indefinite fast by Patkar.
Many people including slum dwellers are joining the relay fast every day at Golibar ground, it said.