Chandni Chowk brings back some memories!
On the topic of eating street food, when I was in India I broke my promise of not eating such foods and was perfectly fine (for the first 10 days anyway

).
Had some really nice spicy noodle dishes from random street vendors as well as some chai to wash it down. To be honest, you can't guarantee the hygiene standards of any random restaurant you walk into off the street anyway so it's worth a go for the taste experience - especially if you can do it in the context of a tour like this where no doubt the vendors are to some good standard ^