Most families do not use car seats in China (they don't even know what is a car seat). Only those who are very rich or foreign-educated will use it. That said, car seat is necessary and helpful. You'd better take one back if you plan to have your baby stay there for a while. Same for stroller and pack N play. Also tell your parents not to use any pillow, quilt, or pad in the crib when she/he is still little.