What leads to an increase in induced drag?

Induced drag rises as the angle of attack increases due to the aerodynamic principles governing lift generation. When an aircraft's angle of attack is increased, it generates more lift until reaching a critical point. At this higher angle of attack, the airflow over the wings becomes more turbulent and creates a greater difference in pressure between the upper and lower surfaces of the wing. This increased lift comes at a cost, as it also leads to a rise in induced drag, which is a byproduct of lift generation.

Induced drag is particularly significant at lower speeds and higher angles of attack, where maintaining lift requires more force. As such, while increasing speed or decreasing altitude can impact drag levels, it is the increased angle of attack specifically that directly correlates with an increase in induced drag. Therefore, the answer is rooted in the nature of lift and drag relationships in aerodynamics.