Garbage

All the garbage that people throw in the water might land on reefs and bleaches(kills)the polyps.Sewage from towns,cities and poisonus waste matierals from factories may end up sorrounding coral reefs.The more dirtier and polluted the water is,the more harder it is for polyps to live and grow.When people cut trees near reefs to make houses and put crops dirt is washed into the ocean,the coral gets coverd by a thick lair of mud wich blocks out the light and evantuly the coral dies.