Rishikesh is a photographer's delight but unfortunately we had a very brief stop there on way to Kanatal from Glass House on Ganges. To add to my woes, there was a slight but continuous drizzle and I did not have an umbrella! Still, I managed a few shots of the few people and the famous bridge.
Sparky - I have no idea! It's situated in the foothill of Himalayas at a height of 532 metres (1,745 feet) so that and may be the clean air brings out that color? I also noticed that it changes colors at different places and times of the day.