Back from my India trip and here's the advice I gathered along the way...
The Indians advised me that washing greens in bottled/filtered water is sufficient (although I'm still not 100% sure whether it's sufficient for our soft western guts!).
For a month I was up in the mountains in north eastern India, a place called Mizoram, in December, their winter. The availability of fruit was restricted, but even so it was easy to get oranges, papaya and bananas. I couldn't find any lettuce in the markets, apparently it is available but hard to find and not reliable. (Thank goodness my mother in law had constructed a greenhouse in preparation for our visit in order to grow our own lettuce.) Other greens were readily available (they had mountains of them in the markets), mostly what they called mustard greens (although I'm not sure if it's the same as the stuff we call mustard greens), however I'm not sure if these can be eaten raw.
I then spent two weeks travelling around India. During this time we were moving quickly and very busy visiting relatives/friends so we didn't have much time to explore and figure out where to source things, but here's what I found:
Kolkata and Delhi - not much fruit around on the streets, probably just the area we were staying in and also the fact that it was winter. We found lettuce and other greens in the supermarkets in expensive shopping malls.
Mumbai - again, their winter, but in winter the weather is still in the 20s so nice and warm, consequently there was lots of fruit available everywhere on the streets. Didn't see any greens on the streets though, again, we had to go to a supermarket in a shopping mall, and even there the quality was quite poor.
Pune - we sayed in Koregaon Park, near Osho's temple and there was plenty of fruit on the streets and a good variety of good quality greens too. In one shop they told me everything was organic, obviously I have no way of corroborating that and you'd still have to wash everything in filtered water anyway to protect against cholera. Needless to say in this area they were catering to a western audience, but the prices were very high.
In general if you're travelling in India I'd say there's probably no point in attempting to find a salad in a restaurant. I've heard in Thailand it's possible to get good large salads, but I can't imagine finding that much in India. Maybe you'd get a decent salad in a 5 star hotel or expensive shopping mall but it would be rare (and the salad would be tiny of course).