What is the ruling on one who is unable to prostrate with his nose and forehead on the ground due to severe crowding in the mosque?

Prostrating on the forehead and nose is an essential pillar (rukn). However, in cases of extreme crowding, it is permissible to prostrate on the back of the worshiper in front, based on the statement of 'Umar ibn al-Khattab, may Allah be pleased with him. This is the view adopted by the majority of jurists, such as al-Thawri, Abu Hanifa, al-Shafi'i, and Ibn al-Mundhir.