Which one should I choose, artificial intelligence in IIT Jodhpur or mechanical at IIT Guwahati?

Artificial Intelligence is a specialization that is expected to be in high demand in the near future and its scope is yet to be determined. I don’t think it’s safe to go for a newly launched field that too from a new IIT. The program and institution both lack the necessary credibility. I would recommend you go for a general branch at a new IIT, a specialization like AI from a well-reputed institute. There are many factors one should consider like faculty, subject content, etc before going for a new specialization. 

Mechanical at IIT Guwahati on the other hand is a very safe choice considering the high credibility of the long-standing Institute.