The use for which a flat is put to is called user. For instance the user of your flat is residential. When you use the flat partially or wholly for teaching of children or students it amounts to partial or whole change of user as the case may be. Any change of user of a flat requires permission of the Managing Committee. If the change of user is of a commercial nature and/ or it will require additions and alterations, after getting the permission of the Managing Committee, the permission of the Municipal Corporation also will be required under the Shops and Establishments Act, 1948. The pupose of permission of the Municipality are two-fold. If the user is for earning the Municipality will increase the tax. If there are employees there are regulations to protect their interests and welfare. Also they have to into whether the nature of work or goods stores would increase fire hazard. There were high court judgements deciding that the activities of doctors, lawyers and chartered accountants are not commercial. A press cutting is attached. Then I do not know why a teacher teaching a few children at primary level should be considered commercial. Unlike the professionals mentioned in High Court judgment, a housewife only supplements the family income. Also unlike the professionals her activity will be only tenporary. The children will go away after a few months. Do not use the word coaching classes. That will invite trouble.
The Society pays insurance premium for the building. The insurance premium may be increased for certain type of user as, in the perception of the insurance company, the risk may be more. While insurance policy is taken the agent will not see all these things and may charge only normal premium. But unfortunately if a claim is to be made the insurance company will bring all these factors and refuse payment of compensation.
There is nothing in law to state that the rights and conditions for sub-tenant are different from that of a tenant-member. If the Society says otherwise you can ask to quote the relevant bye-law or section of the Act. So if a dispensary is permitted and you are told to stop teaching, that would amount to discrimination.
You ask yourself whether you are causing any inconvenience to your neighbors and others in the building. The inconvenience could be because there will be too many foot-wear in the corridor or the children may be making too much noise. If you are convinced that you are not inconveniencing others and no member, particularly none of your neighbors are complaining, you adopt a passive policy. Do not go and ask your landlord member or the Society for permission. Tell the Society to give notice to the landlord member. If the landlord comes to you, then you act. If necessary come here. Things are to be handled not purely based on laws only. The human aspects also have to be considered.