The cause of the caste system was to separate the people from different social hierarchies, thus enabling specialization of the people from certain caste for certain jobs.
The effect of the caste system largely represents and supports the initial cause of its establishing, but there were also other things that were very bad, like the segregation of the people from different castes, restricted communication between the castes, no chance for progressing in life, limiting the people to with whom they can marry.
This system lasted for a very long time in India, being one of the most recognizable traits of the Indian culture and heritage. Nowadays though this system has been abolished in order to make the people more equal and to provide them with the same opportunities in life, as well as to stop the segregation and discrimination.