Singh, 88, breathed his last at the National Heart Institute. He was suffering from kidney-related ailments.
He was ill for quite some time. But he turned critically ill for the past one week, Indu Nihal Singh, his sister-in-law said.
The veteran journalist will be cremated here tomorrow, she added.
S Nihal Singh had worked with several leading newspapers including The Indian Express, The Statesman and Khaleej Times.
He is survived by four sisters.