GST Applicability

Yes sir. If the food is on no-charge basis then GST is not applicable. But if you charge the employees then GST is applicable on the amount charged.

The services of education institution is exempted. Catering services are not exempted from GST. Food provided to staff at subsidized rate is not chargeable to GST.

SAC-9992

Descripttion-Services provided to an educational institution, by way of-catering, including any mid-day meals scheme sponsored by the Central Government, State Government or Union territory;

Rate-Nil

Thus on catering service to school no GST is chargeable, however food provided and to employee and consideration received is chargeable to GST.

Advance Ruling Authority, Kerala in Caltech Polymers Case holding

Canteen by the employer to employee is covered under the definition of supply. [Sec 7(1)(a) of the CGST Act]

The Canteen facility is a business activity carried by the co. ancillary to its main business activity i.e. manufacturing. [being taxable under Schedule II Clause 6 of CGST Act]

So it's taxable AND ...if you are Providing food free of cost then section 17(5) come into the force & ITC has to be reversed

2nd:

Education institutions providing service is exempted not your services being provided to them .