An ambitious free trade deal, covering about 40% of the world economy has been signed in the US. The Trans-Pacific Partnership is expected to phase out thousands of import tariffs as well as other barriers to international trade. It marks the end of five years of intense negotiation and is seen as a major policy victory for US President Barack Obama. However, the deal still has to be approved by lawmakers in each of the 12 participating Pacific Rim countries. Their trade ministers are yet to find common ground on contentious issues- including automobiles, dairy and intellectual property.