Trivandrum, Nov 18 : Thousands of devotees across southern India have begun the 41-day pilgrimage trek to Sabarimala Temple on the foothills of the Western Ghats in Kerala. Abstinence from alcohol, smoking, non-vegetarian food and sexual relations is a part of the ritual that pilgrims are supposed to adhere to. During the "Vratham" period normally all Ayyappas, as those who undertake the penance are called, wear only black clothes and observe 41 days of penance.