bowl
坏 centers on a bowl, a container for holding or serving food.
坏 combines 土 (earth, clay) with 不, which likely contributes the sound. The character suggests a bowl made of clay.
The left side 土 is clay, and the right side 不 looks like a bowl shape with a lid. Picture a clay bowl being shaped on a potter's wheel.
For ハイ, imagine a bowl sitting high on a shelf: high -> ハイ, and the bowl is ready to be used.