Massive traffic was witnessed at Atal Tunnel today as thousands of tourists thronged Himachal Pradesh during the long Christmas weekend. A record 28,210 vehicles crossed the 9.02-kilometre-long tunnel in the last 24 hours, the police said. While more than 14,000 vehicles were from Himachal Pradesh, over 13,000 vehicles came from outside the hilly state, the police data showed.