There's a lot in the question, and it goes back to the international regime on the movement of waste. At the core of it is the Basel Convention, which is an international agreement that Canada signed and ratified. The cornerstone of trade is prior and informed consent, so nobody can send any waste to a country that has not provided its consent first. In doing so, the principle behind it is that the country can assert that it can manage the waste in an environmentally sound manner: i.e., it can be dealt with properly from an environment perspective.
On March 29th, 2023. See this statement in context.