Dear Sir,
While providing such amenities to employees without any recovery, it would be diligent to include such clauses in the terms of employment contract providing all the amenities would be provided to employee in the course of his employment. This stand would effect your TDS deduction towards salary of employees by treating the amenities as Perquisites which you need to take care.
Once these amenities are provided by employer to employee for the employment services provided by employee to employer then the same would get it covered under Schedule III of CGST which would be "neither supply of goods nor supply of services".
However, in relationt to eligibility of ITC on such expenses you need to follow the conditions and restructions provided u/s 16 & 17 of CGST Act.