A Moment Comes, by Jennifer Bradbury
1947, Punjab: a British cartographer working to map out where the boundary between India and Pakistan will be established has three teens in his household:
Tariq, an ambitious young Muslim determined to get the best education so that he can be a leader;
Anupreet, a Sikh girl anxious about her relatives and traumatized herself;
Margaret, the daughter, a disgraced debutante liable to get herself and everyone else into trouble.
Tensions are already extremely high. Tariq is under pressure to participate in mob violence, and he's desperate to stay out of it. Anupreet is, somewhat unfortunately, very beautiful and has already been in danger. And Margaret is bored, frustrated, and clueless enough to blunder into situations she doesn't understand at all. As the violence gets worse, the lives of all three are changed along with the future of India.
Bradbury does a great job of evoking the dangers of border areas in 1947, and she brings in a lot of solid historical detail, even including the corpse trains. Overall it's very good YA historical fiction. Even though you want to bop Margaret one over the head much of the time.