Roy, 81, who has run 115 full marathons, completed his 18th 13.1 mile run with daughter Amrita, a senior planner at Amtrak, America's railway system, running her very first half marathon with a time of three hours and 25 minutes on Sunday.
Running in hot and humid weather Roy clocked 8 minutes more than in his last half marathon run at Whitby Waterfront race in Ontario, Canada, last month. It was his fourth half-marathon in the US this year. The father daughter duo was among an estimated 22,000 runners from all 50 states and 19 countries participating in the 36th annual event.
The half marathon started at Eakins Oval and weaved through downtown and past Independence Hall before running along the Schuylkill River and finishing in front of the historic Philadelphia Art Museum.
Roy, who switched over to half-marathons after a spinal injury in November 2011, took to running marathons at the age of 52 and by 75 he had completed 82 races. He went on to complete his 100th marathon in January 2010.
Roy, a resident of Delhi's Chittaranjan Park, who ran his 115th marathon in Mumbai in January, is a retired wing commander of the Indian Air Force.