Cash limit

no limit 

only condition is that all cash should deposit mention in your 

books and u should explain source of income 

For income tax purpose you have no limit on cash deposit. If you able to prove the source you may not be required to pay tax if it does not represent income.
From banking point of view you may have to pay huge charges irrespective of being from disclosed sources.
That's the difference. You have to shell out either towards taxes or charges