New Delhi: Delhi registered 15 deaths due to the novel coronavirus in the last 24 hours, the lowest number of fatalities in a single-day since July 1.The number of coronavirus cases in Delhi rose to 1,37,677, while the death toll mounted to 4,004 on Sunday.On July 26, there were 21 deaths due to the pathogen, the previous lowest fatality count since July 1.The corresponding figures on successive days were -- July 27 (26), July 28 (28), July 29 (25), July 30 (29) and July 31 (27) and August 1 (26).On June 23, Delhi had recorded the highest single-day spike of 3,947 cases so far.There were 613 COVID-19 cases on July 27, the lowest in the last two months.