NEW DELHI, March 6 -- An elderly couple were among four people killed in separate road accidents across the city on Holi on Wednesday, even as a citywide enforcement drive by the Delhi Traffic Police led to nearly 5,000 prosecutions for traffic violations, police said on Thursday. Samir Roy, 66, and his wife Chhavi Roy, 58 - residents of Shastri Park in east Delhi - were killed after their scooter was hit by an overturned taxi following a multi-vehicle collision on Lajpat Nagar flyover on Wednesday evening, police said. "Preliminary probe revealed that a speeding EcoSport car first rammed into a taxi, causing it to overturn on the flyover. The taxi then struck the scooter," police said. Meanwhile, a total of 4,929 challans were issued durin...