* A widening gas shortage has hurt some alumina producers in China's northern region which have shifted fuel to gas from coal this year, state-backed Chinese research firm Antaike said on Tuesday
* A unit of State Power Investment Corporation in Shanxi province was affected by the gas shortage since last week and it is estimated that its alumina output will be cut by 50,000-60,000 tonnes this month, a company source told Reuters
* The Development and Reform Commission of Sanmenxia city in central Henan province issued an urgent notice on Dec. 16 that gas supply to local alumina producers would be reduced by more than 100,000 cubic meters to secure residential use, Antaike said
* Production of alumina at Kaiman Aluminium Co Ltd and Yixiang Aluminium will be affected
* China's alumina output dropped in November to its lowest level since March 2016 due to government-imposed output curbs during winter to limit smog
* China put on hold an ambitious project to switch to gas following a surge in demand, which together with inadequate storage and pipeline networks, caused a severe supply crunch in many parts of the country and a price surge just weeks into the start of the winter heating season.