Where are you planning to go, OP? We have taken dd to India five times, including once as a baby and twice as a toddler. She has always been fine, and she absolutely loves it there, but you do need to be careful about what you eat & drink, and car seats are an issue!
How will you be travelling around? We had a seatbelt fitted in the back seat of the car that we used, as it had been taken out - didn't cost much, and only took a little while. We take our own car seat but I have heard of inflatable ones - not sure if that might be an option?
When we go, we tend to buy crates of bottled water from a reliable source in Delhi/Gurgaon, and take enough for the whole trip. We like Catch brand or Himalaya. Don't buy bisleri! We also take loo roll and that hand sanitiser stuff is quite useful. You can buy a potty there and carry it around with you. Obviously, this assumes that you'll be travelling around a bit and moving by car. If you're staying in one place and it's a big city, no big deal.
I think it should be fine. We went when dd was 1.10 and she survived on bananas and chapatti!
I also took lots of little snack for her from the UK. The next time we went, she was around 3, and then she just ate the normal food. Avoid salad, fruit that you haven't peeled yourself, ice cream and be careful about milk. DD has always been fine with the yoghurt.
The other challenge we had was friendly people who kept giving dd stuff to eat. You just have to be quite firm and explain that she can't have them! And be prepared for them to pinch dd's cheeks a lot! It's a gesture of affection but it used to make dd cry! Now she just finds it hilarious!
I am most familiar with northern India, urban and rural. I believe that south India is supposed to be much cleaner! 
I think it will all be fine - enjoy!