My wife and I did a cruise from Singapore to the UAE a few years ago. We visited four ports in SW India, including, Cochin, New Bangalore, Goa and Mumbai.
Love the Indian people and the wonderful Indian food.
Traveling on the highways is a bit of a challenge. We did a tour that required us to travel on a small bus for about 1 1/2 hours each way. It seemed like we were going to crash head on into another vehicle about every couple of minutes. Many motorcycles or people cycling as well as trucks, busses and cars. The Indian infrastructure is not that great.
The huge city of Mumbai has slums that you can see while visiting that about half of its people live in. Check out the movie Slumdog Millionaire.
Yes, garbage is uncollected and you don't drink the tap water.
Still, India has a rich history and it intriguing. If you go, do some research on where you will stay and nearby restaurants (you want to eat at nice restaurants, not eat street food). Flights will be long and expensive. If you go, I suggest that you include a few days in New Delhi and perhaps see the Taj Mahal, which would require some traveling.