Yes, state EWS certificate is valid for central government jobs like SSC CPO. There is 10% reservation in central government jobs under economically weaker sections category. Individual who are not covered under reserved categories and whose gross annual family income is less than 8 lakh comes under EWS.

To know more about SSC CPO eligibility, qualifications etc, you can click SSC CPO exam details .

Yes,you can use your EWS certificate of haryana state government while applying to SSC CPO as the EWS reservation is a central government policy, so an EWS certificate issued by any state government is accepted for central government jobs.

But the EWS category certificate must be in the prescribed form given by SSC CPO FORM in their notification otherwise it is not acceptable.

All the best for your future goals..