The Federal Aviation Administration said on Friday that it was taking significant steps to mitigate the risks posed by exhaustion among air traffic controllers, after a series of close calls last year raised alarms about the safety of the U.S. air travel system. Mike Whitaker, the F.A.A. administrator, issued a directive increasing the number of hours that controllers are required …

Twenty-three top Chinese swimmers tested positive for the same powerful banned substance seven months before the Tokyo Olympic Games in 2021 but were allowed to escape public scrutiny and continue to compete after top Chinese officials secretly cleared them of doping and the global authority charged with policing drugs in sports chose not to intervene. Several of the athletes who …

The Senate early on Saturday approved an extension of a warrantless surveillance law, moving to renew it shortly after it had expired and sending President Biden legislation that national security officials say is crucial to fighting terrorism but that privacy advocates decry as a threat to Americans’ rights. The law, known as Section 702 of the Foreign Intelligence Surveillance Act, …