India is a union of 28 states and 8 union territories. As of 2011, with an estimated population of 1.2 billion, India is the world's second most populous country after the People's Republic of China. India occupies 2.4% of the world's area and is home to 17.5% of the world's population. The Indo-Gangetic plains have one of the world's biggest stretches of fertile flat-deep alluvium and are among the most densely populated areas of the world. The eastern and western coastal regions of Deccan Plateau are also densely populated regions of India. The Thar Desert in western Rajasthan is one of the most densely populated deserts in the world. The northern and north-eastern states along the Himalayas contain cold arid deserts with fertile valleys. These states have relatively less population density due to indomitable physical barriers.