Delhi, officially the National Capital Territory, is a city and a union territory of India containing New Delhi, the capital. Lying on both sides of the Yamuna river, Delhi shares borders with Uttar Pradesh and Haryana. Although Delhi and New Delhi are used interchangeably, these are distinct entities, with New Delhi a small part of Delhi.
Buses cater to about 60% of Delhi’s transport demand. The state-owned Delhi Transport Corporation is a bus provider operating the world’s largest fleet of natural gas buses, following a Supreme Court ruling in 1998 that all public vehicles in Delhi must use compressed natural gas.
According to legend, the city was named for Raja Dhilu, a king in the 1st century BCE. The names Delhi, Dehli, Dilli, and Dhilli are all likely corruptions of his name. Some historians believe the original name is Dhilli or Dhillika, while others believe the name could derive from the Hindustani words ‘dehleez’ or ‘dehali,’ both meaning "threshold" or "gateway," symbolic of the city as a gateway to the Gangetic Plain.