European gas prices have plunged to the lowest since mid-2021, when Russia was just beginning to squeeze supplies before its invasion of Ukraine, helping to reverse a surge in inflation and bring relief to consumers. The slump gas futures are down by two-thirds already this year hasn't just eased the pressure on household budgets. It also undermines one of the biggest bargaining chips held by President Vladimir Putin the ability to squeeze the region's gas supplies. With some traders predicting short-term prices could even go negative at times this summer, the picture couldn't be more different from May last year.