What do you advise if a sister is wearing the niqab and is yelled at in public to remove it, esp by her parents or teachers. She wouldn't take it off, but how should she respond? or should she withdraw? should she explain herself? defend herself?

Ustadh AbdulAziz al-Haqqan

U have to decide what is a wise response. As for the ruling of removing it, it is haram as is the fatwa of Imam Ibn Baz Uthaymeen and others.