What: The solar industry has had a rough go of it over the past month, but Canadian Solar (NASDAQ:CSIQ) has been hit harder than most. The stock is down 21% since the start of June on a string of bad developments for the company.

So what: While Canadian Solar is technically a Canadian company, it's really a Chinese manufacturer of solar modules. That's become problematic because the U.S., Europe, and now Canada have put tariffs, or price restrictions, on solar panels they believe have been dumped into their market.

Over the past month, the U.S. Department of Commerce said it would maintain anti-dumping tariffs that were set at 42.3% for Canadian Solar last year. In Europe, officials found that Canadian Solar violated an agreed price floor for solar modules in leu of a tariff. As a result, the company will now face a 43.1% anti-dumping tariff and a 6.4% anti-subsidy tariff in Europe. Maybe the biggest slap in the face was Canada's extremely punitive 82.3% dumping margin for Canadian Solar.  

Now what: These tariffs around the world highlight the challenge Chinese solar manufacturers are facing in today's marketplace. State-run banks have given billions in loans to build manufacturing capacity, including to Canadian Solar, and countries around the world think it has harmed their domestic businesses. This is a major headwind for Canadian Solar, and it'll be interesting to see how management reacts now that it's getting into the development business in both Canada and the U.S.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.