Essentially, a co-operative housing society is a membership-based legal entity made of one or more residential buildings. You become a member by buying shares in the housing co-operative. In return, as a member, you get the right to occupy a housing unit in the society, be it an apartment or a house. Main object of a co-operative society is Acquiring land, constructing flats and distributing them among the members. Promoting economic interests of the housing society and encouraging self-reliance among members. Disadvantage of co-operative society is As the members of a cooperative society belong to different cultural and social aspects their thinking varies, which leads to a greater possibility of conflicts and therefore it is govern by The Co-operative Act of various states in India and standard bye-laws. 

In case of apartment each apartment owner shall be entitled to the exclusive ownership and possession of his apartment [in accordance with the Declaration executed and registered as required by section 2 of this Act.] Each apartment, together with its undivided interest in the common areas and facilities appurtenant to such apartment, shall for all purposes constitute heritable and transferable immovable property within the meaning of any law for the time being in force in the State: and accordingly, an apartment owner may contribute to their share towards common maintenance and other expenses. Even Apartment Ownership is also an association of person registered and are having bye-laws to govern their association. 

A Co-operative society has a managing committee as well as an apartment association also has a board of managers. Functions of both bodies are similar to each other. Both body performs their duty and responsibility according to bye-laws, the committee can collect maintenance from members, development fund, sinking fund etc from society members, both committees are liable to do day to day work like paying the light bill, water bill, salary of the watchman, manager if appointed. Most important if a member does not pay maintenance for several months, then let us know what rights the society and apartment have – If a member fails to pay maintenance, the committee of the co-operative society can make an application to the Registrar of Societies under section 101 of the Co-operative Act and cancel the membership of such member and sell his flat to recover the arrears of such maintenance. Even if your apartment is an association now you can appeal to the society register for the same reason so now friends tell me what is the difference between a society and an apartment.