New York City Health Commissioner Dr. Oxiris Barbot resigned Tuesday over clashes with Mayor Bill de Blasio and his handling of the coronavirus pandemic. “I leave my post today with deep disappointment that during the most critical public health crisis in our lifetime, that the Health Department’s incomparable disease control expertise was not used to the degree it could have been,” Barbot wrote in her resignation email. The departure comes after the city’s top public health officials have criticized the mayor’s decision to place the responsibility for coronavirus contact tracing with public hospitals rather than the health department, which has years of experience managing such programs.