Boojho's uncle was hospitalised and put on dialysis after a severe infection in both of his kidneys.

(a) What is dialysis?

(b) When does it become necessary to take such a treatment?

(a) The process of filtration of blood by an artificial kidney is called dialysis.

(b) In some people, the kidneys stop working, due to some injury or infection. In such patients, the blood is not filtered and the wastes start accumulating in the body, which may be toxic. Therefore, it becomes necessary to filter blood artificially. And hence, dialysis is done.