OK, that will not work.
ON the Blackberry, not appending any connection parameter means "give me the default transport". This will work on some devices, but not on most. On the simulator, this works because the MDS emulates a BES-connected device (carrier agnostic).
So, you'll need to obtain the APN info from Airtel, and append ";deviceside=true", along with the APN information to your URL.
See these articles:
Different ways to make an HTTP or socket connectio... - BlackBerry Support Community Forums
Specify APN information for a direct TCP connectio... - BlackBerry Support Community Forums