China has imposed a temporary ban on exports of helium to take effect immediately, as analysts said the country was moving to ensure its domestic chipmakers could maintain production amid a severe disruption in global supplies of the gas.The announcement – issued by the Ministry of Commerce and the General Administration of Customs on Friday – did not specify any destination markets or exemptions, implying that the ban applies to all overseas shipments.Helium, a by-product of liquefied natural gas production, is a critical input for a range of sectors including semiconductors, medical equipment and aerospace.Global supplies of the gas have come under severe strain in recent months amid the US-Israel war on Iran, which forced a major facility in Qatar to close and affected shipping traffic through the Strait of Hormuz.China is heavily reliant on imports of helium, with more than 80 per cent of its supplies coming from overseas, according to Chinese commodities data provider SCI99.“This reads as a clear defensive move,” said Alicia Garcia-Herrero, chief economist for Asia Pacific at French investment bank Natixis.