Union ministers Harsh Vardhan and Ravi Shankar Prasad led celebrations to mark the maiden International Yoga Day in West Bengal on Sunday.In the non-BJP ruled state, Prasad, the communications and IT minister kicked-off celebrations at the SAI complex in Kolkata's Salt Lake in sync with the main event at Rajpath while Vardhan, the Science & Technology, Earth Sciences Minister headlined the event at Kharagpur."World Yoga Day generating tremendous response among Nehru Yuva Kendra volunteers,students and youth. Feel proud to be with them in Kharagpur," Vardhan tweeted.Vardhan urged people to participate in the "largest expression of unity"."On World Yoga Day please participate in the largest ever expression of 'unity' thanks to our PM's initiative. World feels indebted to our PM," he said.