As I mentioned earlier, Tai Chi is in infant stage in India. There are very few certified masters around to provide you with authentic training, suitable to your medical conditions. When it comes to chronic ailments such as Diabetes, Arthritis, one needs to be selective.
Since Tai Chi is based on Martial Arts (in slow form), many ex-martial arts trainers have opted for being Tai Chi trainers.
JustDial.com is one of the renowned search engine to find Tai Chi trainer around you. Logon to JustDial.com, give your location and contact number, name etc. and look for 'Tai Chi training center' in your area of preference. JustDial.com will display the names of centers near you. You can opt for any of your choice.
Health Libray in Fort, Mumbai is another source, where you can get ample of information on various health related topics. The following video may be useful for evaluation..