A shocking and fatal stampede near Saudi Arabia’s Grand Mosque at this year’s Muslim pilgrimage has brought serious calls for a review of the Saudi government’s initiatives to protect the safety of the two million annual visitors who perform the Hajj. As reported in The Guardian, the government’s initial reports of 769 deaths occurring from a crowd crush near Mecca have been revised up with total deaths from the stampede now estimated at over 1,000. The incident echoes that of the Hajj in 1990, whereby 1,426 pilgrims lost their lives in the holy city.

Saudi authorities had taken preventative measures to prevent injury following the death of 350 people in the 2006 Hajj. Measures included increasing security personnel and significant renovations to expand the Grand Mosque. However, as BBC News reported, the safety risk lies not so much in the structures of the site, but in the “sheer number” of people travelling within confined spaces that surround the Grand Mosque.

Crowd density and flow rate within a space are key factors to consider when developing strategies to prevent harm arising from overcrowding.