Tds on internship

Dear Sir,

I need some clarification on TDS deduction on internship:-

1. We have hired 3 interns out of which one intern has completed 3 months and left the organisation. Her internship fees was Rs.25,000 pm - Paid for 3 months Rs.76,613/-(we have not deducted TDS)
2. Other two interns contract extended till march and their internship fees is Rs.10,000 pm & Rs.7,500 pm. Paid till date Rs.17,609/- & Rs.29,677/-

We have not deducted TDS considering interns to be as similar to salary and if they do not cross the slab rate then there is no need to deduct.

Please give your opinion on the same.