Hello aspirant!
Hope you are doing well,
In most states of India, the validity of ews certificate is 1 year. To check whether the validity of your ews certificate is 1yr or 6months you must check the official state website of Department of revenue.

EWS certificate is required when you have qualified the examination and it is shown at the time of verification of document.t that time it should be valid.
The simple thing is the procedure of renewal is same as process of applying for EWS certificate. Just visit the authority with the your updated financials of new new financial year to get a new EWS certificate.
Hope this helps!