i cleared my 11th 12th as regular student from cbse but since I have 49% in pcb, am appearing for cbse improvement exam as a private student my 12th pass certificate is from my school regular one only it's just that my improvement marksheet will be written as a private candidate am i eligible neet?

Hey,

Yes, You are eligible for NEET but only if you have passed with minimum 50% in aggregate ( considering your improvement marks) with physics, chemistry, biology/biotechnology, and English. You can apply even if you applied as a private student because the eligibility criteria states that you must have completed 10+2 or equivalent qualification with minimum required marks. Also, you can upload your marksheet or passing certificate which states you marks. You can contact helpdesk In case of any queries.
For more details, check the link below

: https://medicine.careers360.com/articles/neet-eligibility-criteria

Hope this helps!