lost on time when opponent had no mating material

opponent had a bishop , i had a pawn, my time ran out, he won, when did these rules become standard and is it fair ?

I presume it is this game

If you promote your pawn to a bishop or a knight, then your opponent can checkmate you.
This is fully in accordance with the FIDE Laws of Chess: if you lose on time you lose, except when no series of legal moves exists that leads to checkmate. Here such a series of legal moves leading to checkmate exists, so you duly lost on time.

Yes it is that game .
So if my opponent did not know that and i "blundered" my pawn it would be a draw if my time ran out or maybe in the moment he takes the pawn ?

Yes, if he takes the pawn then it is a draw.

great to know, thanks for answering, and by the way do you think it is a fair rule ?

FIDE Laws of Chess:
6.9 Except where one of Articles 5.1.1, 5.1.2, 5.2.1, 5.2.2, 5.2.3 applies, if a player
does not complete the prescribed number of moves in the allotted time, the game is
lost by that player. However, the game is drawn if the position is such that the
opponent cannot checkmate the player‟s king by any possible series of legal moves.

Of course it is a fair rule: you agreed to play a certain time control and you overstepped the time limit you agreed on, so you lost on time.

I did not know that this rule existed before today, so I will say it is unfair the first time you encounter it.
I don't think players at my level spend their time reading FIDE rule books ,so hopefully I will be able to take advantage of this rule in future games.

So you don’t know the basic rules of the world‘s chess association? Actually, a „thank you“ should be enough. Or who is to blame for your lack of knowledge?

Unfair!? People are strange.

Your opponent still could checkmate you.

You don't know the real rules so you invent your own ones and think it's unfair that the real rules are the ones that apply?