Hi Manish,
This is your problem:
"my main gateway is installed at Europe and am trying to access it from Asia region."
You may see some improvements if you upgrade to v9.1 for your GW and Policy Manager but I would not be overly optimistic. It is best to be on the latest version, so you should start there and see what happens.
To upgrade to v9.1 you must install the relevant patches to your v9.0 GW and restart. Instructions here:
Upgrade, Migrate, Patch, Back Up, Restore - CA API Gateway - 9.1 - CA Technologies Documentation
You must also download the v9.1 version of the Policy Manager, which you can do from the CA Support site with your CA account.
Note that you can download all the relevant v9.1 patches and the v9.1 Policy Manager info from the same location on the CA Support site.
-case-