Ayurvedic tourism has become very popular since the 1990s, and private agencies have played a notable role in tandem with the initiatives of the Tourism Department.[1] Kerala is known for its ecotourism initiatives which include mountaineering, trekking and bird-watching programmes in the Western Ghats as the major activities.[172] The state's tourism industry is a major contributor to the state's economy, growing at the rate of 13.3%.[173] The revenue from tourism increased five-fold between 2001 and 2011 and crossed the ₹ 190 billion mark in 2011.