People often tends to confuse Maestro cards with mastercards. They are actually two different type of cards used entirely for different purposes.
In India the default card issued from almost all banks are the Maestro cards. All nationalized banks including SBI Group of banks does the same. Maestro cards are useful to use for simple debit card usage like withdrawing money from atms. paying bills etc, but their transfer of funds is severely restricted and as such Maestro cards can not be used for Online Shopping, On-site bill payment etc
MasterCard Debit Card in turn facilitates transfer of funds in very dynamic manner. It is accepted all across the globe and can be used to different purposes like On Line and Retailer shopping. A MasterCard can be used wherever a MaestroCard can be used, Hence MasterCard is much more preferable than Maestro Cards
MasterCards are only issued to customers who specifically request for it. If you are presently own a Maestro Card and wants to get a MasterCard you will have to surrender your existing card to your bank and apply specifically for a new MasterCard.
Major banks in India may charge you a little if you are applying for a MasterCard. At present it is around Rs100
Update: As some readers have pointed out Maestro cards are being accepted by some Indian Online retailers. But MasterCards remain the standard for international money transactions