The Canadian government is tightening mortgage lending rules to reduce risks in the housing market. They are making it harder for people to get mortgages by testing their ability to handle higher interest rates and limiting how much they can borrow. This is because Canadians are taking on more debt than ever before, and the government wants to prevent a financial crisis like the one in the US in 2008. The goal is to protect the economy and make sure people can afford their homes even if interest rates go up.