I've seen several. I've seen water snakes in Kerala, and also snakes that I was told not to get any nearer, there were dangerous.
In my own garden, the year before last, we had a couple of rat snakes. I know people see cobras further out of Chennai, although I never saw any snakes further in to the city.
Apparently (we had a snake catcher come the first time we saw one) they hear very little, but they feel low-frequency vibrations, so they know who is walking around, and yes... they would rather avoid than attack.