In India, What is the maximum amount of cash that an individual can keep with him legally?

In India, What is the maximum amount of cash that an individual can keep with him legally without paying any tax?? I am salaried and have paid income tax. Over the years, i have got back the personal loans given to friends and relatives and it is in cash…Do i need to give tax for that amount again?? Or else, is there any governement regulation on maximum amount of hard cash(currency) that an individual can keep with him ( Not in a bank)??