If your EWS certificate is valid for the required year, then there will be no problem regarding it and you can use it as a valid document for any purpose. Now if you think that as its blurred you may face problem, then you can take a xerox copy of the document and get it signed by an Gazetted officer which declares that the document is fine. It would be better if you can do it from DM's office. But in general it will not cause any problem for you.

The eligibility for the EWS certificate are:

• The annual income of the family of candidate should not exceed 8lakh per annum.
• The family should not hold 5 or more than 5 acres of land.
• The family shouldn't have a residential area more than 1000 sq feet.
• The family shouldn't have a residential plot (in notified municipalities) of an area 100 square yards or more.
• The family shouldn't have residential plot (other than in notified municipalities) of area 200 square yards or more.

I hope this answer helps. All the very best for your future endeavors!