am 10+2 with the commerce background and then i pursued B.Sc from delhi university college and then post graduate diploma in public health and dietitics am below 25 can i appear for neet examination

Yes once you graduate from b.sc. you could apply for NEET. The 25 year old age limit which was previously imposed has been removed. Also it means you have already passed +2 so yes you can apply. 

Yes, you can apply for NEET entrance exam after your B.Sc. 

The Eligibility to apply

As per the latest Government order, the age limit for NEET 2017 has been removed. Previously, it was 25 years, the candidates of this age and above were not allowed to appear for the NEET.

You should have minimum 50% in class 12th to apply for the exam as a general Category.

Good Luck!