HI,

YOU did not mention about your caste category, however reservation is available for sc/s t / obc, now for sc/st certificates there is no particular date mentioned, however   the Caste Certificate should clearly mentioned about

: (a) Name of candidate caste/ tribe (b) whether applicant belongs to SC or ST (c) District and the State or Union Territory of applicant’s usual place of residence, and (d) the appropriate Govt. of India Schedule under which his/ her caste/ tribe is approved as SC or ST. if the certificate is not available you may submit the acknowledgement slip, but at the time of admission original certificate need to produce.

for obc ncl caste certificate , certificate should be issued as per DOPT Office Memorandum No. 36036/2/2013-Estt. (ResI) dated 31 March 2016).

If the applicant does not have the OBC ncl certificate of the latest financial year 2019-2020 at the time of registration, the applicant may upload the previously issued (older) OBC non-creamy layer certificate or the acknowledgement slip of OBC non-creamy layer certificate application. However, at the time of admission, the applicant must produce the recent financial year’s (2019-20) OBC non-creamy layer certificate, issued by the same certifying  authority.

for more information follow the below link,

http://du.ac.in/du/uploads/COVID-19/24062020_UG.pdf