Internship Contract Related- Possible Consequnces of Breech

Hi, I'm currently working as an Intern in an organization. The initial duration was 2.5 months which was mentioned in the offer letter but not the internship contract, but now I need to cut it short by month due to personal commitments. But they're not letting me do that. They said that they'll only let me leave if I will complete the said tasks, which I don't think I have the time for. If you might need to know, the reason is that I need to prepare for my GRE and TOEFL exams which I only have dates for in July ending so I can only work until the end of June or 2 more weeks at max. So 2 points to note are- 1. The end date is not explicitly mentioned in the Internship Contract I signed 2. I signed an NDA which is in accordance with the India Contract Act of 1872. The contract was signed by me and I never received the counter-signed document. Although I have been working for them for a month or so now. I'm willing to share the documents if required, but I really need to know if there will be any legal consequences if I decided to stop working them with or without them formally closing it. I mean, what if I just send an email to the concerned authorities stating that I will not be able to work hereafter. Please let me know as soon as possible. Thanks & Regards