Government leaders from Asia have pledged to boost air quality control programs in some of the most polluted cities of the world. As Chad Bouchard reports from the Indonesian city of Yogyakarta, widespread urban smog threatens economic growth and is blamed for more than a half-million premature deaths each year.

The withdrawal from Abéché in eastern Chad of non essential United Nations staff, including those working for the World Health Organization (WHO), has left refugee and displaced populations and local communities facing a potential health crisis, WHO said today.