SHANGHAI—China faces mounting pressure to ramp up coal imports and ensure supplies to keep lights on, factories open, and water flowing as a severe power crunch roils the northeastern industrial heartland. With electricity shortages sparked by coal shortages crippling large sections of industry, the governor of Jilin province, one of the hardest hit in the world’s no.2 economy, called for a surge in coal imports, while a power company association said supply was being expanded “at any cost.” News organizations and social media carried reports and posts saying the lack of power in the northeast had shut down traffic lights, residential elevators, and 3G mobile phone coverage as well as triggering factory shutdowns. A utility in Jilin even warned power shortages could disrupt water supplies at any time, before apologizing for causing alarm. For the second straight day, the main state grid operator sought to reassure customers, saying it would …