The union representing school administrators has written a letter to Mayor de Blasio and Schools Chancellor Richard Carranza, asking them to delay the start of in-person learning past September 10th.

In the letter, the Council of School Supervisors and Administrators says they have been left without sufficient answers to many of their concerns.

Once individual school reopening plans are submitted this week and then approved, the council says teachers will have less than 15 working days to prepare.

"The task before them is simply not possible to complete while simultaneously providing assurances of a safe and secure learning environment,” the letter reads in part.

The council says a more realistic approach would be to begin in-person learning towards the end of September.