its the mist which later turn into water .
@350Z get your headlight checked there is small hole(not visible to naked eye) or crack from where this mist is entering i had similar problem with our santro long ago . it was very very small hole .
@350Z get your headlight checked there is small hole(not visible to naked eye) or crack from where this mist is entering i had similar problem with our santro long ago . it was very very small hole .