Outside of major tourist places, or even inside them, avoid eating raw foods. Only drink bottled water in India.
Smog in the cities can be bad and unhealthy, especially during the dry season.
The Indian unit of money is the rupee. For your safety, do not display currency valued at more than 500 or 1,000 rupees in public.
Don’t walk alone at night.
Indian cities usually have at least several internet centers that allow you to pay by the hour.
Be careful of the taxi drivers around Bangalore because they constantly try to make you pay more than you are supposed to.