I also find that any place which has only recently (comparitively speaking) become a part of India is much cleaner and more disciplined than the rest of the country...Goa and Sikkim are what I base this observation on. Sikkim is so lovely....waterfalls everywhere, greenery, people who are genuinely friendly.....we had a fabulous trip.
Another factor is the presence of the Army everywhere in the hill areas...the roads are maintained by them, and perhaps they contribute to the feeling of overall discipline...the work being done on the landslide sites shows how much of effort goes into maintaining the hill roads in motorable condition. I am very impressed.
In Kolkata today....enjoying nostalgia, as I visit scenes from the past...amazing, the buildings which were ramshackle and ready to break down 30 years ago, are there in the same condition today! However, orbital roads are excellent, as is the Metro. My spouse would like to live here, he says!
Resolving to travel as much in India as possible as long as both of us are in good health!