See there are no such given specification of time range for which you can say that your EWS certificate will be ready. So if you need it on emergency, you must visit your SDO/DM office and request the official in written regarding your emergency of the certificate. It may get considered accordingly but nothing can be concluded for sure.

To know more about SSC CGL 2021-22 visit the link below:

https://competition.careers360.com/articles/ssc-cgl-application-form

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