Delhi is one of the few cities of the world where the total public transport is run on environment friendly compressed natural gas.
Qutub Minar, which is situated in the southern part of the city, is the world's tallest brick minaret.
Jama Masjid, which is situated in Delhi, is India's largest mosque. It was built during the reign of Mughal Emperor Shah Jahan. 5000 workers worked for six years to build it in 1656.
Delhi has more than 20% of green cover, which makes it one of the greenest cities of the world.
Khari Baoli, Delhi's oldest spice market is Asia's largest wholesale spice market.
The walled city or Old Delhi too was founded by Emperor Shah Jahan by the name of Shahjahanabad in 1649. The walled city was originally surrounded by a high wall and fourteen gates. Today, only five gates exist, which are Ajmeri Gate, Lahori Gate, Kashmiri Gate, Delhi Gate and Turkman Gate.
Maharaja Sawai Jai Singh founded Jantar Mantar in 1724. It has 13 architectural astronomy instruments. One of them can precisely calculate the distance between earth and sun.
Delhi Metro is the fastest growing railway network of the world. It has daily ridership of almost 3 million passengers.
10. Also known as Bahai Temple, Lotus Temple is one of the finest crafted structures is in Delhi.