Q. What is knee airbags - Swift?

These are additional airbags i.e. from main 2 standard from airbags which are for protection of your knees in case of an impact. usually top end models of medium to high range cars have these available. other wise in low to medium range cars we have side curtain airbags to protect you from side impacts.

Knee airbags are those protruding which come out from below the steering during the crash to protect the knees from getting injured. They are standard as per European auto mobile rules. But i am not sure of their deployment in automobiles in Indian market. May be only Skoda offers them i think in India.