Too high ping

I live in France and I usually get 45-55 ping, but now for at least a week I've been getting theses abnormally high pings like 250 in some rooms. It's like when I enter a room and I get a 250 ping then it will stay like that until the end of the game and then in another random room I get 60 ping and it will stay quite stable. I wonder what could cause this.