From the article: "Solar panel prices tumbled around 30 percent last year after China, the world's largest producer, cut subsidies to shrink its bloated solar industry, pushing smaller manufacturers to the brink of collapse."
This is exactly the opposite of price fixing. They subsidized the market (consumption) and created a bloated industry. Removing the subsidies lead to overcapacity and hence a drop in prices below the rate of a healthy market.
This is exactly what is happening again this year. The difference is that we are seeing more than 50% price drop.
If you look at the fraunhofer PDF, you will notice that chinese companies own 95% of the market now. The way they were allowed to scale was by targeted chinese subsidies on PV projects that were not accessible to outside tenders.