You cannot file a backdated challan, but you have to register the employee now and pay his contributions with a retrospective date as a contribution on omitted wages. Obviously, it will attract interest and damages as well.
If you are knowledgeable about any fact, resource or experience related to this topic - please add your views. For articles and copyrighted material please only cite the original source link. Each contribution will make this page a resource useful for everyone. Join To Contribute