I had EWS certificate from Central Government is it useful for state quota admission?
Yeah! It may help. EWS reservation is applicable for the state government decisions. If the state in which you reside agrees to give 10% reservation in state government colleges and jobs then you will definitely get benefited through this system.
Although central colleges and universities has this quota as a compulsory level.
So do check that your state government allows the reservation or not. Probably all the governments gives reservation but for your own benefit you should search the internet about your state allows or not.
If you are from WEST-BENGAL then yes you will get the reservation benefit but for other just check it so that you don't have to face any problem in future.
Hope my answer helps you. Wish you a prosperous career ahead!