is a legal entity - usually a corporation - that owns real estate; one or more residential buildings. Each shareholder in the legal entity is granted the right to occupy one housing unit, sometimes subject to an occupancy agreement, which is similar to a lease. The occupancy agreement specifies the co-op's rules. Cooperative is also used to describe a non-share capital co-op model in which fee-paying members obtain the right to occupy a bedroom and share the communal resources of a house that is owned by a cooperative organization.
Co-ops are more commonly known as "flats" in India. This type of housing is very common in big cities like Mumbai (Bombay) but not very popular in rural India. Actually, they are registered as "co-operative housing society" rather than condominiums in that the owners actually have a share of the co-op and not the actual real estate itself. Owners can sell the "share" in the open market, but they have to get the approval of the co-op to complete the transaction.
this is some info from my side