Holy cities face threat from polluting pilgrims

November 8, 2011
By George Webster
CNN

(CNN) – An estimated 2.5 million pilgrims have descended on the city of Mecca for the Islamic Hajj, said to be the largest annual gathering of people in the world.

Every fit and able Muslim is obliged by their faith to make the journey at least once in their lifetime. But with the rising threat of climate change, there are now calls for both pilgrims and authorities in Mecca to reduce the environmental damage wrought by this yearly influx of travelers.