Different surname in Aadhar and 10/12th Marksheet for NEET-UG

It is known fact that what ever name appear in Aadhaar must tally with the educational certificate since the change of name in the certificate is cumbersome process,it is better to change the name in Aadhaar by submitting the proof of your educational certificates.

Dear Mr Mohan,
The surname on my Aadhar card had the old surname previously but I was required to change it for my ST certificate. I am only allowed to change this twice in my life and I have done so once already. If I change it back to my old surname then I will not be able to change it back to the new surname again.
Kindly advise keeping this in mind.
Thanks.

Also, changing my name of my Aadhar card does not seem to be the right solution as the surname on my ST certificate is also the new one which I cant change. So when I upload my ST certificate, I'll have the same problem.

I, belonging to Tamilnadu, did my Hindi certificate course through an Institution of North India and on completion, I got a certificate as Ms. Rama Chandran (denoting as female). This is because of a gap while entering the name. I wrote a letter to them by mentioning the same and got the certificate with the correct name.

Aadhaar is an Identity form introduced by our Government that should be unique to all citizens. Since our country is wide and secular in religion, language and rituals, etc., we cannot expect every part person should know other parts' practices. Further, the entry made in the records of Aadhaar by persons belonging to various states, languages the difference in pronouncing or keeping spellings found common. we can get corrected in Aadhaar by approaching the concerned authorities with relevant documents. The correcting authority will definitely understand the situation and do the corrective measures. For this you are required to approach in person the nearby Aadhaar center where you can get corrected without any difficulty.

You need to approach a lawyer and you should discuss the whole issue. I think he would be able to sort out your problem. Since your Aadhar Card has been updated enclosing your ST status but the same is not not appearing in your class ten and twelve certificate retaining old surname.
The lawyer would make a fresh affidavit stating that the name appearing in the Aadhar Card and the person holding the certificates of class ten and twelve are not different but the same. He would make an affidavit accordingly and the same would be produced before him along with the photocopies of the original documents to get his signature in the affidavit. Your signature would appear in the left side of the document.
Once you get the affidavit, get the same published in two distinguished papers - one in local paper and the other in the English Paper. Preserve the cutting to be used in course of document verification stage whenever necessary.

Presently, at the time of applying in NEET your surname is changed from what it had been in your 10th and 12th educational credentials. So, you cannot go back now to that and have to mention your new surname in all the coming activities in your educational career. You can mention a note about this in the NEET application form in remark or any other information column so that your candidature will not be rejected. While uploading 10th and 12th certificates and mark sheets in the online NEET system you can mention it if there is a facility of uploading additional information. You will be uploading your Aadhar card and caste certificate also and that would make the things clear. I do not think that your application would be rejected. Only care you have to take is that at the time of document verification and other credential assessment you should have all the legal affidavits ready with you to show that your surname was changed in a legally valid way and that was the reason of mentioning the new surname in the application form. Keep all the original documents ready for the document verification session when you qualify in NEET and are called for counselling.

While filling the NEET form online please take care in giving correct data as on date and if the system prompts that your surname in the application or in Aadhar car or in the Caste certificate is not matching with that of the SSC and HSC certificates then you have to ignore it and go ahead. The online application systems have many facilities like that and go through it meticulously to go ahead in those steps. Please read the system prompts with utmost care or take help of some experienced person while filling the form.

You can also meet a lawyer for bringing clarity in the matter and he will also be able to advise you as what should be the legally valid path in such situations.

Already you have an affidavit and paper advertisements regarding your surname change. After that, you have changed your surname in Aadhaar card also. That is fine.
Your 10 and 12th mark sheets were issued before the issue of this affidavit. In the affidavit made you might have mentioned your old name and the new name also. So it is very clear that your 10th and 12th certificates will have your old names only. But after the affidavit, you have to mention the new name only in all the places.
You should fill in your changed name only in your NEET application and you can use Aadhaar as the ID proof. No chances are there for rejecting your application. If you can upload your affidavit also while applying it will be very good. If there are no chances for that you can carry them with you when they call for document verification. You can just upload a small piece of information saying about the change in the surname if there is any chance.
Meanwhile, I suggest you go for the Gazzette publication of your name. The procedure will be known to the lawyer who helped you in doing the affidavit. Once your name is declared in Gazzette, you will not have any problems in future. You can consult a lawyer and ask his opinion also if you want.

Update:
Today I spoke with the NTE helpline number and they advised me to fill the surname which is on the 10th Marksheet only since that is what the Information Bulletin states and also at the time of filling the online form there is a popup which states the same. I have this conversation on record. I asked them if this will be a problem since my name has already been changed as of date and I am filling the old surname, she told me that it should be the case since the form asks me to fill the information as per the 10th Marksheet and my 10th Marksheet still has the old name. I further questioned if my ST certificate will be rejected since it has the new surname, she said no since documents can be submitted at the time of Medical Counselling verifying that the two names belong to the same person.

Now speaking to them I understand that my form should not get rejected if I mention the same details as per marksheet. However, the admission process is handled by Medical Counselling Committee and they should not have an objection to me appearing the exam with the old surname.

My written email to NTE received a blanket response stating that I should fill the form as per the guidelines.

If anyone can guide me, I shall be very grateful.

@DR.N.V. Srinivasa Rao
@Umesh
I have filled the form with a fake name and there is no provision of uploading any additional documents or remarks at any place.

@DR.N.V. Srinivasa Rao
I've already gotten the information published in the State Gazette as well.

@Sheo Shankar Jha
All the steps mentioned by you have already been done as stated in my original post.