The southern region of Asia's continent comprises the countries of Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan and Sri Lanka and houses a substantial portion of the world's population. Because Southern Asia is the most densely populated geographical region in the world, the oil and natural gas industry serves as a significant generator of income, and is vital to powering the region's newly industrialized and developing cities, including such major metropolises as Mumbai and Delhi in India, the most populous democracy in the world. An economic rebirth in Southeast Asia within the last decade has spurred new investment in the oil and natural gas sectors.