Sitting in the still, sunny courtyard of Tower Hill private school in Delaware, Zara Ali talks about her favorite city in the world: Mumbai. India's commercial capital, Mumbai -- crowded, dynamic, colorful -- is 13,324 kilometers and cultures away from Wilmington, Delaware -- a historic American town with fewer than 100,000 people. This month, among rolling hills and lush gardens, Ali graduated from the small private school of 700 students. “Sometimes it’s difficult to feel like you have a global outlook” when ensconced in the leafy Brandywine region of the mid-Atlantic U.S. But her teachers a...