Better, not the best
I wasn’t really happy by the design of the application, which included polling. Now I have changed the design in the sense that constant polling will still be there, but content of polling will be different. So, the client and the server both maintain time stamps for their respective objects (which client need to load as soon as it changes at the server end). Let tc be time stamp at the client side, and ts, the time stamp at the server side. During polling, if the ts==tc, there is no transfer of data from server to client. And if tcts, is undefined, and just indicates an error.
This still is not the best solution, which would be using asynchronous communication from the server to the client. Which would use technology like pubsubhubbub.