Respected Pundalika Achyutha Bhat,
Housing boards provide share certificates, which are legal documents or certificates. It verifies that the resident is the rightful owner of cooperative housing society shares. It is provided at no cost to members of housing societies and is required by their by-laws.
Possession of a member's share certificate by a co-operative housing society without justifications is likely to be treated as illegal possession.
However, it must be noted that the original copy of the share certificate will be with the Secretary or any other person of authority as mentioned by the board.
You can directly ask a person to return your share certificate if he/she has taken it with no justification or you can contact the police or the board regarding your inconvinience.