EWS reservation is for those Candidates that belong to General Category and who do not claim any reservations that are available for OBC,SC,ST. Now a General Category is a General Category across India. Now there are few Communities that belong to BC at State level and belong to General Category at Central Level. They can be checked under Central OBC list. But there is no such Central EWS list. Your State issued EWS Category is valid across India. So if you have EWS reservation and a Certificate, you can claim EWS reservation at both Central and State level Counsellings.