What is Asymmetrical Information? -Why may this Happen?

-This is when Buyers, or Sellers, know more information, and that information itself is imperfect -this may be because the service they provide is unpredictable - health services will not know when someone will be ill, and with what -or moral hazard. this is when people take risks because they will not suffer the consequences if it goes all Wrong, but rather someone else will. banks know the government will prop them up if they get in trouble, so therefore, they do riskier behaviour. the government lacks information about how banks therefore will act.