Yes, non-resident ,PIO, OCI card holders can also apply for SRMJEE 2021. You must pass 12th standard to gain eligibility . SRM college has released the application form on 12th December 2020 and the last date to apply the form is 31st March 2021. You can find the form in the official website of SRM.
For futher details I'll paste a link below
Hope this helps you