It's in the article:
Over the last decade or so, China has seen a shift from older AGM batteries, which are heavy and bulky, toward lighter and longer-lasting lithium-ion batteries.
However, safety concerns regarding rare yet dangerous lithium-ion battery fires have put a pause on that proliferation. The government instituted new safety standards for lithium-ion batteries in e-bikes last year, but there’s also been a major pushback toward AGM batteries for the domestic market.
LOL, that episode popped in my head when I read that.