Dear Student ,

No, Only diploma holders are not allowed for UPSC exam . To be eligible for UPSC , you need to be graduate in any Discipline from a recognized University .

and in Case of UPSC ESE exam, you need to do B.Tech four year course from a recognized University .

To know more about UPSC eligibility Criteria , refer this :

https://competition.careers360.com/articles/upsc-ias-eligibility-criteria

Hope this helps !