OCI card mandatory?

[0xim]

https://indianvisaonline.gov.in/

The last line in the advisory reads: For persons of Indian origin (all categories), OCI card is mandatory.

Does this mean a person of Indian origin can't get a visa or an e-visa? If you have OCI card, you don't need a visa anyway. I am confused by what this means.

Thanks.

[Jot18]

Currently only OCI holders and people holding emergency visa are allowed.