Is it permissible to wear the niqab during Umrah due to shortness of breath and the presence of young children?

It is forbidden for a woman in ihram for Hajj or Umrah to cover her face with a niqab or anything specifically designed for the face. If she needs to cover her face due to the presence of non-mahram men, she should let down something from above her head over her face. If it touches her face, there is no sin upon her and no fidyah (expiation) is required. However, if she covers her face with a niqab or similar without necessity, then fidyah is incumbent upon her.