The 17-day pilgrimage to Manimahesh Lake in Himachal Pradesh, sacred to Lord Shiva devotees, began Sunday.
"Over 20,000 pilgrims left on the first day of the pilgrimage," Additional District Magistrate Lakshmi Kant Sharma told IANS.
Over 250,000 people are likely to undertake the pilgrimage through the Bharmour Valley in Chamba district. It is considered just as arduous as the Amarnath Yatra in Jammu and Kashmir.
Every year, the Manimahesh pilgrimage begins on the eve of Janmashtami festival dedicated to Lord Krishna's birth and concludes with Radhashtami (the birth of Lord Krishna's consort Radha). This year it will conclude Sep 2 when thousands of devotees would take a dip in the lake.
Officials said the annual "Chhari Yatra" or the procession of Lord Shiva's mace would start from the 1,000-year-old Lakshmi Narayan temple here to the Manimahesh Lake Aug 26. It would reach the lake Sep 2.
The state government has made it mandatory for devotees to get themselves registered for the yatra.
The devotees undertake the arduous 14-km trek from the Hadsar base camp, 65 km from Chamba town, some 450 km from the state capital Shimla, to the oval-shaped, glacial-fed Manimahesh Lake, located at an altitude of 13,500 feet, from where they can see Mount Kailash, believed to be the abode of Lord Shiva, and take a dip into the lake.
Officials said the devotees started reaching the lake two days in advance.
"Over 50,000 people are expected to the reach the lake on the first day (Aug 17)," said an official.
In the past two days, four people died due to medical reasons and accidents.
The government has deployed 50 rescue workers to handle any emergency and banned carrying of goods in polythene bags.
The state government has allowed two private heli-taxi operators to ferry people during the pilgrimage.
The choppers ferry devotees between Bharmour town, the base camp of the pilgrimage, and Gauri Kund, just one km short of the lake. The one-way fare per person is Rs.3,270.
