The Tangshan city authorities in Hebei province, China, may extend and deepen cuts to steel production in order to control pollution. The current cuts, equivalent to 15% of capacity, have had an outsized effect on exports. Shipments from mills around Tangshan fell 54% in December vs. a year earlier to hit the lowest since at least 2013. Among major export lines steel bars/rods fell 82% and high-speed steel slumped 98%. The impact on total Chinese steel exports shouldn’t be overstated though as the city only accounted for 5% of exports in 2016 and 3% in 2017. More important will be the U....