The Trump administration claimed without evidence Thursday that California is failing to protect its residents from water pollution caused by homeless populations in San Francisco and Los Angeles. Environmental Protection Agency chief Andrew Wheeler said in a letter to Governor Gavin Newsom that California is failing to enforce the Clean Water Act. Wheeler’s letter came three days after he threatened to pull billions of dollars in federal highway funding to California, accusing it of having the worst air quality in the U.S. California and nearly two dozen other states filed a lawsuit earlier this month challenging the Trump administration’s efforts to roll back California’s more stringent tailpipe emissions standards. A spokesperson for Governor Newsom called Trump’s moves “political retribution against California, plain and simple.” And San Francisco Mayor London Breed said, “There are no needles washing out to the Bay or ocean from our sewer system, and there is no relationship between homelessness and water quality in San Francisco. It’s just not a real issue.”