The World Health Organization warned yesterday that new advances in technology have made it possible for terrorists to kill millions of people with chemical or biological weapons. The draft 179-page report was rushed out after calls for advice on how to combat germ warfare. The World Health Organization released the report as it emerged that an order would be issued in the U.S. today grounding all crop-dusting planes amid fears that those behind the September 11 attacks may have been plotting to use the aircraft to spray chemical or biological weapons.