Expenses deduction from Income

Right Method is that the expenses claimed should correspond to the income earned. If at all u want to claim some expenses u should produce the bills on when ur case is selected for scrutiny otherwise u can escape the wrath of the Income tax. So it a risk 

Rakesh, you are right but still there is some percentage which IT department also consider as genuine before asking for bills.

Suppose anyone earning 10lakh and showing 3 lakh as expenses, so this will consider as correspond to the income earned.