If the Aadhar number on your admit card is incorrect, you need to contact the college or the exam conducting authority to have it corrected. Here are the steps you can follow:

1. Contact the Exam Authority: Look for the contact details of the exam conducting body which should be mentioned on your admit card and reach out to them immediately. Request them to correct the Aadhar number on your admit card.

2. Check the Official Website: Visit the official website of the exam conducting body and check if there's an option for "Correction Request" or "Admit Card Correction."

3. Email or Helpline: If there's no option on the website, you can email or call the helpline number provided by the exam body. Make sure to include your correct Aadhar number along with other details like your exam roll number or registration number.

4. Correction Form: Some exam bodies provide a correction form. If they do, fill it out and send it along with the correct details.

5. Proof: You might be asked to submit proof of your correct Aadhar number, such as a copy of your Aadhar card.

Try to address this issue as soon as possible to avoid any problems on the exam day.