Have you run out of the balance and are in dire need of mobile balance just to make an emergency call?
If you are an Ncell user, then there's a way you can get the recharge of Rs.20 for free! It's not absolutely free, but you do not need to spend the money right at the time when you use it. It's a loan provided by Ncell to you just to make sure that you can make that emergency call. Ncell will charge back that amount (Rs.20) when you recharge your mobile next time. For this to work, your balance must be less than or equal to Rs.2.
Simply make a call to *9988# and you'll be sent Rs. 20 immediately. You cannot ask for a loan again unless you clear the one that you already possess. Ncell will cut-off Rs.20 when you recharge your mobile next time and once again, you'll be able to request for Rs.20 loan, in case you run out of balance.
Note : The actual amount of loan is about Rs.22. Some of the amount is taken off as tax.