Edit. After Black September's assassination of Israeli athletes at the Munich Olympics in 1972, Prime Minister Golda Meir okays a black-box operation to hunt down and kill all involved.
Yellow pollen is produced by evergreen trees, primarily pine trees, including spruce, true cedar trees, fir trees, larch and hemlock. Although yellow pollen looks like it could cause an allergic reaction, in reality it does not trigger allergy symptoms at all. It can stain the skin and clothing, however.
Answer Wiki. Pollen from plants which have evolved to attract them. To entice bees and other pollinating creatures in, plants produce flowers which are often brightly coloured, scented and provide pollen or nectar as a food reward. The pollen can be all sorts of colours too, from blue-black to green.