SACRAMENTO — Striking a blow against a pernicious form of pollution, Gov. Gavin Newsom signed into law Thursday the nation’s most far-reaching restrictions on single-use plastics and packaging.

The legislation heads off a November ballot measure that many lawmakers and the plastics industry hoped to avoid, and it puts California at the forefront of national efforts to eliminate polystyrene and other plastics that litter the environment, degrade into toxic particles and increasingly inhabit human blood, tissue and organs.