The document discusses monthly price changes of yellow phosphorus in China in 2011. It notes that prices rose dramatically from September to October, reaching a peak of over $3,000 per tonne in October. While prices declined in the second half of October, they remained at a high level of around $2,783 per tonne in mid-November. The price is expected to remain elevated for the rest of the year due to continuing strong demand, constrained supply during the dry season, and increasing production costs.