
allocated in a project, but not been assigned with any task from last 2 months
we came into this project, but later we got to know that there is no requirement in this program, but they didn't deallocate, now what to do ?

Better not to talk anything now. As long you receive allocation, you are safe. If at all you get to know something like, say associates might be released very soon in near future, there is a feasibility for your name to be put in RMG Fluidity list. To avoid that situation in future, discuss peacefully with your supervisor and move out, that too only after finding another project

how to find another project while still being allocated?

I don't know. If you try checking with your friends and know where there is a vacant role, you can politely request them to be released from WON without release to RMG. RMG can approve WON movement based on mutual consent between two projects/accounts/WON Owners. This happened during the mid of 2021 while TCS offices were fully closed during Covid Pandemic situation.
