In the current situation, everyone in Singapore is generally required to wear face masks when going out. This also encompasses Muslims. Having to conduct 5 daily prayers, some of them might have to do so at their workplaces or at nearby mosques. 

A Muslim is able to pray while wearing a face mask without having to take it off. This includes during prostration (sujud).

The physical nature of sujud is to ensure that these 7 body parts touch the ground: Part of the forehead, the two palms, the two knees, and the two feet (toes).

From here, we are able to understand that wearing a face mask during sujud is permissible & does not invalidate the prayer.

This is in line with the guide (irsyad) the Office of Mufti has provided. 

Let’s play our part in battling COVID-19!