Public transport in Delhi is provided by buses, auto riskchaws, a rapid transit system and taxis. Click here for a road map of Delhi.

Bus

Buses are the most popular means of transport catering to about 60% of the total demand. The state-owned Delhi Transport Corporation (DTC) is a major bus service provider for the city. They also boast of the world's largest fleet of environment-friendly Compressed Natural Gas (CNG) buses. To find out more on bus routes, click here.

Auto-rickshaw

Three wheeled auto rickshaws or autos are the most used means to commute within the city as they charge a lower fare than taxis. Most run on Compressed Natural Gas (CNG) and are yellow and green in colour. While most rickshaws have an electronic meter that displays the fare at the end of the journey, they are generally not used and a fare is negotiated before a journey. They can take in upto three passengers and offer a cheap and quick option of commuting.

Rapid Transit System

The Delhi Metro, a mass rapid transit system built and operated by Delhi Metro Rail Corporation (DMRC), serves many parts of Delhi. As of 2007, the Phase-I of the metro is operational and consists of three lines with a total length of 65 km (40 miles) and 59 stations while several other lines are under construction, causing constant traffic jams and an unusually large amount of dust, even by Delhi standards. Massive construction on Phase II is underway.

Taxi

Taxis are not an integral part of Delhi public transport, though they are easily available. Private operators operate most taxis, and most neighbourhoods have a taxi stand from which taxis can be ordered or picked up. In addition, radio taxis can be hired by calling a central number. These are usually air-conditioned and charge a flat rate of Rs. 15 per kilometre.

Source:
http://en.wikipedia.org/wiki/Delhi