You can find more detailed information about projects and infrastructure in Mecca, but I found this article a good overview about how S. Arabia plans to deal with the ever-increasing storm of pilgrims:
Mecca makeover: how the hajj has become big business for Saudi Arabia
Country's religious tourism industry booming
New luxury hotels prove huge draw for pilgrims
Mecca makeover: how the hajj has become big business for Saudi Arabia | World news | The Guardian
Mecca makeover: how the hajj has become big business for Saudi Arabia
Country's religious tourism industry booming
New luxury hotels prove huge draw for pilgrims
Mecca makeover: how the hajj has become big business for Saudi Arabia | World news | The Guardian