That's not regulating the production of steel, but adding a tariff on an industry. You could obviously block someone from selling in your country, but that does

That's not regulating the production of steel, but adding a tariff on an industry. You could obviously block someone from selling in your country, but that doesn't mean you have the right to regulate them. Just like you could block a website within your country. That said, you can't force them to adhere to anything. Put a different way, if I run a news paper in Russia, sure you can block the distribution in the EU. The EU cannot tell the news paper what to publish.