As most people impacted by this are already aware, EB-3 India petitioners retrogressed 3.5 years this past visa bulletin. Once a visa retrogresses, there are very limited options that can help until it becomes current again. Interfiling may be a possibility for some.
There is another potential solution if you are willing to take action before retrogression occurs. If your petition is current and retrogression is a real risk, consider filing a mandamus lawsuit to finish the process and get your approval before retrogression puts you back in limbo.