‘Cutt-off date’ is a date decided by the State Government to determine the eligibility of slum dwellers for the Slum Rehabilitation Scheme. The slum dweller must prove that the dwelling structure existed on/before the cutt-off date and that he/she has been living in that dwelling structure prior to the cut-off date. If the slum dweller is unable to establish this, then he/she might be completely ineligible to participate in SRS or be part eligible (wherein he/she gets a house but on payment of a premium).
There is a GR published in 2018 that clearly outlines the rules of eligibility.