The challenge was filed by 26 companies who argued that increased import duties imposed by the 28-nation bloc on solar panels and related photovoltaic technology is hurting efforts to fight climate change.
The accelerated tariffs were imposed after a two-year long investigation by the European Commission found Beijing was improperly subsidizing manufacturers and that the panels were being sold on the continent at a price well below their true market value.
The anti-dumping and anti-subsidy duties have an average rate of 47.7 percent.
In a written statement, the General Court said it "confirms the validity" of the measures.
However, the long-term fate of the duties is uncertain. Since 2013, the European Commission has been moderating its stance. Earlier this month, it proposed extending import duties on the panels by a shorter than initially proposed 18 months and eventually phasing them out.
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