Himachal Pradesh witnessed a fresh spell of mild snowfall on Saturday
Amid a festive rush, more than 55,000 vehicles entered Shimla in the past couple of days for Christmas weekend.
Massive traffic jams were witnessed in Shimla, Manali and Kasol which witnessed a fresh spell of snowfall on Saturday.
About 55,000 vehicles crossed the Atal tunnel in Rohtang - that joins Kullu and Lahaul and Spiti - in the past three days, officials said.
Several videos have surfaced on social media showing a long queue of vehicles on roads.
Sanjay Kundu, Director General of Police, Shimla appealed to the tourists to prioritise safe travel practices and adhere to traffic rules.
Officials said more than 1 lakh vehicles are expected to enter Shimla this week for New Year celebrations.
According to police data, about 60,000 vehicles remain parked on the roadsides in the city. On an average, about 12,000 vehicles enter Shimla on weekdays, with the number rising to over 26,000 during the weekends at the height of the tourist season.
The 9.2-kilometre Atal Tunnel is the world's highest single-tube tunnel above 10,000 feet.
Chief Minister Sukhvinder Singh Sukhu praised the efforts of the district administration and the police for "efficiently managing" the huge tourist influx.