Question

what are the causes of river pollution? and what are its preventions?

Answer 1

River pollution is caused by
Industries which are built near rivers release give out harmful gases which mixes with water
Washing clothes /utensils etc in rivers
It can be prevented
By stopping these activities

Answer 2

River pollution are caused by improper dumping waste,flow of untreated sewage waste into river,flow of industrial waste water,etc.
It can be prevented by stoping discharge of untreated waste into water,waste water should be treated first,we also must takes some steps by helping in river water cleaning program.