I gave a partial answer with my first point.
At the end of the day, the buyer of a product will determine how it will be used. For example, Canada has the highest standard for diesel fuel, with a sulfur level of 15 parts per million. The standard in Mexico is 500 parts per million. That country has different environmental restrictions.
If someone wishes to do business in Canada, they need to respect the environmental standards established by Environment Canada. For example, nothing prevents a producer from selling any given product in Mexico, in South America or in any other countries. Once again, the needs of the buyer will determine the quality of the product.