LONDON/TOKYO—Global factory activity accelerated in November although crippling supply bottlenecks remained, putting a cap on output and driving up the cost of raw materials, according to surveys published on Wednesday. Towards the end of the month, the newly-detected Omicron coronavirus variant emerged as a fresh worry for policymakers, who are already trying to pilot recovering economies and tamp-down inflation. The November surveys likely did not reflect the spread of the variant, which could add further pressure on pandemic-disrupted supply chains, with many countries imposing fresh border controls to seal themselves off. “The Omicron variant … could be a game-changer: shortages of inputs and labour would worsen for manufacturers if Britain and other countries went into another lockdown,” said Samuel Tombs at Pantheon Macroeconomics. IHS Markit’s final manufacturing Purchasing Managers’ Index (PMI) for the euro zone nevertheless nudged up to 58.4 in November from October’s 58.3, shy of an initial 58.6 …