two house property

I HAVE TWO HOUSE IN MY NAME . I WISH TO KNOW THE THE TAX IMPLICATION UNDER FOLLOWING CASES :

1) BOTH THE HOUSES ARE VACANT AND NO ONE LIVED THERE  ANYTIME DURING PREVIOUS YEAR OR ANY YEAR.

2) I LIVE IN ONE OF MY HOUSE AND THE OTHER IS VACANT AS LIKE IN ABOVE .

3) I LIVE IN THE HOUSE AND MY RELATIVES OR ANY FRIEND LIVES IN THE OTHER AND I DONT TAKE ANY RENT FOR THAT .

 KINDLY HELP IN KNOWING THE TAX IMPLICATION IN THE ABOVE MENTIONED MENTIONED CASES . THANK YOU !