Tripura lies in a geographically disadvantageous location in India, as only one major highway, the National Highway 8, connects it with the rest of the country. Five mountain ranges—Boromura, Atharamura, Longtharai, Shakhan and Jampui Hills—run north to south, with intervening valleys; Agartala, the capital, is located on a plain to the west. The state has a tropical savanna climate, and receives seasonal heavy rains from the south west monsoon. Forests cover more than half of the area, in which bamboo and cane tracts are common. Tripura has the highest number of primate species found in any Indian state. Due to its geographical isolation, economic progress in the state is hindered. Poverty and unemployment continue to plague Tripura, which has a limited infrastructure. Most residents are involved in agriculture and allied activities, although the service sector is the largest contributor to the state's gross domestic product.