Hard to believe, but one of my positive experiences in crowded New Delhi was to take the Metro.
India of course has been in the news for all the wrong reasons lately; sadly, sexual violence is pervasive in the country. For single female travelers, that means having to be careful.
Like Cairo, Tokyo, Beijing, and Rio de Janeiro, New Delhi reserves subway cars for women to spare them from being groped or harassed. A safer place, and finding yourself amid a group of women, cross-cultural conversations quickly start—a great side effect.
The other positives are: it is cheap (no need to haggle with a rickshaw driver if you're not in the mood) and it is fast (no road traffic to fight).