India and Bhutan Saturday crossed another milestone in bilateral economic relations by signing a defining agreement on setting up a new Rs.35 billion hydel project that will provide power to the South Asian giant. Visiting External Affairs Minister Pranab Mukherjee and his Bhutanese counterpart Lyonpo Khandu Wangchuk inked the landmark agreement for the largest-ever hydel project to be built in the Himalayan Kingdom with Indian assistance. The 1,095 MW Punatsangchu-I plant, a run-of-the river project, is expected to be completed in eight years to become yet another symbol of hydel power emerging as a key pillar in Indo-Bhutanese relations, the Press Trust of India (PTI) reported today. "The agreement is historic and takes mutually beneficial cooperation to greater heights," Mukherjee told reporters on the second day of a three-day official visit to the Himalayan Kingdom.