He was 55. He is survived by his wife.
Majumdar, who was National Affairs Editor at NewsX, was suffering from Acute Myelocytic Leukemia (AML), one type of blood cancer.
He was admitted to the Apollo Hospital in Sarita Vihar last week of January and was diagnosed with blood cancer just 15 days ago.
He was in the intensive care unit (ICU) at the hospital for the last four-five days and "died this afternoon", a hospital source said.
Majumdar was earlier national affairs editor at CNN-IBN.
Rahul Shivshankar, editor-in-chief of NewsX, said, "Diptosh had a unstinting commitment to the craft of long form journalism and he wanted to explore news event in deeper perspective and weave a broader narrative around events -- political and social."