Kathmandu is the capital and largest municipality of Nepal. It also hosts the headquarters of the South Asian Association for Regional Cooperation. It is the only city of Nepal with the administrative status of Mahanagar , as compared to Upa-Mahanagar or Nagar. Kathmandu is the core of Nepal's largest urban agglomeration, consisting of Lalitpur, Kirtipur, Madhyapur Thimi, Bhaktapur and a number of smaller communities in the Kathmandu Valley. Kathmandu is also known informally as KTM or the tri-city. According to the 2011 census, Kathmandu Metropolitan City has a population of 1,003,285 and measures 49.45 km2.