Even the temperature change can induce delhi belly.
Tips would be to drink bottled water & avoid ice in your drinks, use bottled water to rinse your toothbrush.
When I went ot india I got the runs about 3 weeks in. I thought I'd got away with it. Take imodium incase you need to travel on bus journeys or return flight. Otherwise it's best to let natrue run it's course. Multivitamins & a couple of packs of anadin extra are worth packing too imo