The exams began at 215 centres across the country at 10am on Friday
The abrupt blockade led to huge tailbacks on both ends of the road.
Witnesses said nearly 1,000 workers of four garments factories took out a procession around 8:30am in Khilkhet disrupting vehicular movement.
Thousands of office-goers were stranded on their way to work.
Police tried to talk the protesters off the road on several occasions without success.