के_लिए: Circumstance ~> Circumstance

In this context के लिए means "on the occasion of." Arguably this is related to the Purpose↝Purpose sense of के लिए.

Is perhaps Circumstance↝Purpose a better fit?

• जन्मदिन
  birthday

  के_लिए
  for

  क्या
  what

  किया
  did

  ?
  ?

  'What did you do for your birthday?' 001