Chinese solar companies are engaged producing polution.
Chinese solar companies are manufacturing solar cells that are of obsolete design and whose total lifecycle energy cost is about equivalent to the total lifespan energy output. The environmental damage from the manufacturing process is huge.
By ensuring these Chinese cells are not dumped in the US it become much more viable for advanced technology (such as sliver cells) to be produced in the US. The environmental cost will be reduced, the TCO of solar installations will be reduced and the more advanced cells being produced will be far more energy positive that the imported ones.
Chinese solars cells are little more than frozen coal powered electricity and are not helping the environment one iota. By adding these tariffs the net effect is an improvement to the environment. Win, win, win.