A 75-year-old American swimmer took a dip in the Seine River on Thursday, braving the murky waters in central Paris to celebrate the Fourth of July and highlight the French government’s efforts to clean up the river for the Olympic Games.

He had good timing: Hours later, regional authorities released data showing water quality in the river improved over the past week, raising hopes it can host Olympic swimming events after all.

Joel Stratte McClure, who last swam in the Seine in 1976 for a magazine cover shoot and turns 76 this month, said he was impressed with the progress made in cleaning up the river, but still had concerns about its safety.

“I may regret having swum,” McClure said before entering the water. “But if I come back alive, it will prove that the French have done a good job cleaning up the river.”

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Paris Mayor Anne Hidalgo initially planned to swim in the Seine last month to prove its cleanliness — prompting an online campaign by her many critics threatening to poop in the river on the day of her dip.

But she postponed the swim after President Emmanuel Macron announced snap legislative elections that have plunged France into political tensions and eclipsed pre-Olympic excitement for many. Heavy rainfall in recent months has also translated into faster-than-usual currents for this time of year, and Hidalgo says she will swim in the river in mid-July instead.

“I think the president organized new elections to avoid swimming in the Seine,’’ McClure joked.

After a brief swim, he declared the water “fantastic” and expressed hope that others would follow his lead and take advantage of the cleaner river.

Marathon swimming and triathlon are scheduled to take place in the river near the Alexandre III bridge during the Olympics, which run from July 26-Aug. 11, and the Paralympics, which run from Aug. 28-Sept. 8.

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Unsafe levels of E. coli were found in the river last week for the third consecutive week. But on Thursday, regional authorities released new results showing an improvement.

The test results by monitoring group Eau de Paris show that for all but one day from June 26 to July 2, contamination levels were below the safe limit of 900 colony-forming units per 100 milliliters determined by the World Triathlon Federation for competitions.

French officials remain optimistic, and insist there is no Plan B for Olympic open-water swimming events.