CUT-OFF MARKS UPSC CSE varies from year to year. It depends upon the number of factors like the number of vacancies, number of candidates, types of questions asked in the examination.
Below is the table
To download from UPSC website visit: https://upsc.gov.in/examinations/cutoff-marks
UPSC CSE is conducted by the UPSC every years : See the time table for year 2020
The Cut-off marks are decided by the UPSC at the time of declaration of result. It is decided based on vacancies, marks scored by candidates.
It varies every year because it depends upon the number of vacancies, number of candidates, types of questions.
UPSC publishes the cut-off marks for Civil Services Examination after the final result gets published.