Interest income from sundry debtors

Dear All,

I have some commission income from a share franchisses and got form 16. But I have some interest income from lending business (about Rs.70000/-).

How I treat this income in computation of total income. I have not maintain any books for income from money lending.

Is this income from other sources ?  

Please let me know all legal requirments about the problem.

Thanks 

H S BAGGA