Power rationing and forced cuts to factory production in China are widening amid electricity supply issues and a push to enforce environmental regulations.    The curbs have expanded to more than 10 provinces, including economic powerhouses Jiangsu, Zhejiang and Guangdong, the 21st Century Business Herald reported Friday. Several companies have reported the impacts of power curbs in filings on mainland stock exchanges.  Local governments are ordering the power cuts as they try to avoid missing targets for reducing energy and emissions intensity. The country’s top economic planner last month flagged nine provinces for increasing ...